Held Hostage

I went into Ackermans South Gate yesterday Th April 2015 to take out a lay-bye I had made worth 2600. I didn't have my lay-bey slip but when I produced my ID the cashier was more than happy to let me pay 2300 to get my goods. I was then given a receipt with the lay-bey code as proof that I had paid in full for my goods. When I got home I realised that I didn't' need some of the things so today the 26th April 2015 I went back with the prof of payment and the clothes still with price tags on. I was then advised by the manager that since I didn't' have the original receipt I will get a gift card instead of my money back. If that is the case why did Ackermans take my 2300, why was I not turned back!!! I do not want a gift card. This is just a plot by retailers to hold customers hostage since the gift card means I can't spend my money anywhere else but Ackermans. I have a right to return what I no longer want as long as it is still in the condition it was when I left the shop. I have kept my end of the \contract"and now Ackermans must keep theirs. I DO NOT want your gift card I want my money back and would appreciate it if I could get it back. IT IS MINE."""