Pass listItem data using command from button in MVVM

I am working on an app that will allow the user to pay for a Utility Bill. It allows for multiple utility accounts to be linked to one user. I have a list view that properly displays the information, in each ListItem Template i need to pass the value from the label to the ViewModel using a button. If this is ansered else where please let me know, i have searched for days and nothing so far has worked.

Here is my View:

<ContentPage.BindingContext>
        <local:UtilityViewModel/>
    </ContentPage.BindingContext>
    <StackLayout>
        <ListView x:Name="UtilityAccts"
            ItemsSource="{Binding Items}"
            HasUnevenRows="true"
                  SelectedItem="{Binding SelectedItem}"
            SeparatorVisibility="Default"
            SeparatorColor="#0b4996"
            CachingStrategy="RecycleElement">
            <!--Built in Cells-->
            <!--<ListView.ItemTemplate>
        <DataTemplate>
                <TextCell Text="{Binding UtilAcctNum}" />
            </DataTemplate>
    </ListView.ItemTemplate>-->
            <!--Custom View Cells-->
            <ListView.ItemTemplate>
                <DataTemplate>
                    <ViewCell>
                        <StackLayout>
                            <Grid Padding="10">
                                <Grid.RowDefinitions>
                                    <RowDefinition Height="auto"/>
                                    <RowDefinition Height="45"/>
                                </Grid.RowDefinitions>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition Width="*"/>
                                    <ColumnDefinition Width="*"/>
                                    <ColumnDefinition Width="*"/>
                                </Grid.ColumnDefinitions>
                                <Label Text="{Binding UtilAcctNum, StringFormat='Account#: {0}'}" Style="{DynamicResource ListItemTextStyle}" Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2" HorizontalTextAlignment="Start" TextColor="Default" />
                                <Label Text="{Binding AmountStr, StringFormat='Amount: ${0:C}'}" Style="{DynamicResource ListItemDetailTextStyle}" Grid.Row="0" Grid.Column="1" Grid.ColumnSpan="2" HorizontalTextAlignment="End" TextColor="{Binding DueColor}"/>
                                <Button Text="Pay $" BackgroundColor="Green" TextColor="White" Grid.Row="1" Grid.Column="0" BorderRadius="4" BorderColor="YellowGreen" BorderWidth="2" Command="{Binding LoadPay}"/>
                                <Button Text="Remove -" BackgroundColor="Gray" TextColor="White" Grid.Row="1" Grid.Column="2" BorderRadius="4" BorderColor="LightGray" BorderWidth="2" Command="{Binding Remove}"/>
                                <Button Text="History"  BackgroundColor="Green" TextColor="White" Grid.Row="1" Grid.Column="1" BorderRadius="4" BorderColor="YellowGreen" BorderWidth="2" CommandParameter="{Binding UtilAcctNum}" Command="{Binding LoadHistory}"/>
                            </Grid>
                        </StackLayout>
                    </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
        <Button Text="Add +" BackgroundColor="Green" TextColor="White" BorderRadius="4" BorderColor="YellowGreen" BorderWidth="2" Command="{Binding AddUtilAcct}"/>
    </StackLayout>

and here is my View Model (some info redacted)

public class UtilityViewModel : INotifyPropertyChanged
    {
        #region UtilityList
        public event PropertyChangedEventHandler PropertyChanged;
        private ObservableCollection<MobileUtilityAccountView> _items = new ObservableCollection<MobileUtilityAccountView>();
        public ObservableCollection<MobileUtilityAccountView> AccountList = new ObservableCollection<MobileUtilityAccountView>();
        private MobileUtilityAccountView _selectedItem;

        public Command LoadPay { get; }
        public Command LoadHistory { get; set; }
        public Command Remove { get; }
        public Command AddUtilAcct { get; }

        public ObservableCollection<MobileUtilityAccountView> Items
        {
            get
            {
                return _items;
            }
            set
            {
                _items = value;
                OnPropertyChanged("Items");
            }
        }

        public MobileUtilityAccountView SelectedItem
        {
            get
            {
                return _selectedItem;
            }
            set
            {
                _selectedItem = value;
                if(_selectedItem == null)
                {
                    return;
                }
                else
                {
                    OnPropertyChanged("SelectedItem");
                }

                SelectedItem = null;

            }
        }

        public UtilityViewModel()
        {
            GetAcctNumbers();

            LoadHistory = new Command(HistoryCmd);
        }

        private void OnPropertyChanged(string v)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(v));
        }

        private async void GetAcctNumbers()
        {
            string path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "Verified.txt");
            var fileContent = File.ReadAllText(path).Split('|');
            string ID = fileContent[0].Replace("\"", "");
            HttpResponseMessage response = new HttpResponseMessage();
            HttpClient client = new HttpClient();
            Uri uri = new Uri("******************);
            response = await client.GetAsync(uri);
            if(response.IsSuccessStatusCode)
            {
                var content = await response.Content.ReadAsStringAsync();
                Items = JsonConvert.DeserializeObject<ObservableCollection<MobileUtilityAccountView>>(content);

                for (var i = 0; i < Items.Count(); i++)
                {
                    if (Items[i].UtilAcctAmtDute > 0)
                    {
                        Items[i].AmountStr = Items[i].UtilAcctAmtDute.ToString();
                        Items[i].DueColor = "#cc0000";
                    }
                    else if (Items[i].UtilAcctAmtDute < 0)
                    {
                        Items[i].AmountStr = Items[i].UtilAcctAmtDute.ToString().Replace("-", "") + " CR";
                        Items[i].DueColor = "#00cc00";
                    }
                    else
                    {
                        Items[i].AmountStr = Items[i].UtilAcctAmtDute.ToString();
                        Items[i].DueColor = "#00cc00";
                    }
                }
            }
        }

        private void HistoryCmd(Object obj)
        {
            LoadHistoryPage(obj.ToString());
        }

        private async void LoadHistoryPage(string utilAcctNum)
        {
            var page = new NavigationPage(new UtilityAccountDetailsPage(utilAcctNum));
            NavigationPage.SetHasNavigationBar(page, true);
            NavigationPage.SetBackButtonTitle(page, "Back");
            page.Title = "";
            await App.Current.MainPage.Navigation.PushAsync(page, true);
        }
        #endregion
    }

Here is a screenshot of the emulated View: