You can view all payments received in the Web Portal, by going to Accounts > Payments.
And find them in the App by going to Accounts > Payments.
Swiping to the left on the payment in the app will allow you to undo the payment or open the invoice attached to the payment.
A history on each invoice will populate when any changes are made once it is created. This will show payments being edited and removed from an invoice to provide full visibility on activity.