To record a return, you have to create a Debit Note.
Let's say you have purchased a laptop from ABC Co. for $1029.99. So you will first enter this purchase as a Bill and make its payment entry to record the purchase. After 2 weeks, you returned the laptop. Then you will record a Debit Note towards ABC Co. for $1029.99 and then make its refund (Debit note) to the bank account.