If you have been told that you cannot pay more than the amount due it could be for one of two reasons:
The payment has been entered manually:
In this instance, check if the payment has been added manually. If so, and the record is correct, you can ignore the error message.
You have entered a payment more than the invoice amount in Commusoft:
In order to rectify this, open the relevant job. Click on the payment method and you will be able to edit this payment to a valid number. Click 'Save'. You will then need to resend these failed records.