No refund policy

My husband purchased a book for me as a birthday gift. Unfortunately I already have the book. Today we went to return the book. I tried to find another book but to no avail. We then requested a refund, the store refused. According to the sales lady it is store policy not to give any refunds and that my husband should have read the small notice at the bottom of the glass door when he purchased the book. They offered a voucher however I advised that I don't want a voucher but rather a refund. I have even called the manager on her mobile as she was not in the store but she was also not able to assist. Which is very important to mention is that when he purchased the book he asked if he can return the book should it be necessary and they said yes. They have not mentioned they don't do refunds only vouchers. In my opinion it it ********* behavior. I have left the store with the book as I hope to resolve this with senior management.