Refunds made to customers and sales returns is not same

The receivables’ account at 1 May had a balance of $32,750. During May, sales of $125,000 were made on credit. Receipts from receivables amounted to $122,500 and contras with the payables’ account of $550 were allowed. Refunds of $1,300 were made to customers. What is the closing balance at 31 May on the receivables’ account?
Answer in the Book:$33,400 debit.
I am not convinced with the answer in the book. My answer is $36,000 debit. Book has treated refunds made to customers as sales returns but I am not happy with this. Please kindly explain this sir.