Requesting for a refund

I made a lay-by at that shop last year then this year when l went there to tell them that l no longer want that thing am asking for a refund they said that they don’t do refunds that l must take something else then l did but then the problem is that l only changed the product because they were forcing me to take something because of “no refund policy “ and the is nothing l want at that shop as they don’t always have stock.