Adding products in order and send the payment difference

[gabriel81mi]

Hello, I am try to understand if there is any possibility or module that can send to customer the payment difference.

I'll explain the possible case.

The customer forgot to add products after placing and paying for a new order, call customer service and ask for the option to add product x.

The product is added by administration, the new order now is greater than what has already been paid by the customer.

how could this price difference be requested from the customer? is there a way to send the email with the payment bank link? 

thanks in advance