Terrible service

Worst service recieved from retail store. Cashier is rude and unhelpfull. I bought stuff which do no fit on my curtains. The cashier as well as the manager then told me i cant get a refund only a store gift voucher (the receipt clearly state i paid cash not a gift card) so why must my refund be in a gift card? After the service received why will i want to shop there again?