Angry customer

I have been lay bying a gas heater for 3 months and when my hubby went to pay it off and collect it he was told we need to give notice for 1 month as the stock they have in store is not working its broken brought back by other dissatisfied customers and they nearly gave him a heater which was brought back by someone else. he asked for a refund and we he was told to bring receipts and every month we have been going to the store without a receipt to pay and we would give the cashier the ID number we were never told of having receipts. We are highly disappointed and want our refund back.