Bad Debt

Upon writing off a bad debt, we already have a bad debt account set up, I have created the customer return already for my client:

The issue is upon processing the return in the process customer return screen, choosing the client return I had created already and proceeding to apply it by clicking on apply to an invoice tab,  the client name does not appear on the apply to an invoice screen along with the invoice details to apply the return amount against? 

It will not allow me to click on the client name field to add their name either? Normally the client name appears on this screen automatically along with their invoice details to allow you to apply the return?

Please help with this query.

Thanks