Selling wrong Products

Bought an Ipad mini 4 cover from Gadget World. They gave me the wrong size (was for a Mini6), After I asked a couple times if the cover is for an Ipad mini 4. Took back with in a week. They did not have the cover in stock I needed and wanted to give another. I was not happy with the replacement cover and requested a refund. They refused saying it is 'not my business and do not give refunds" Bad services, do not know they products and sell you the wrong items. Stay away!