OK Furniture sucks!

I'm a student and made laybye at OK Zeerust. I decided to cancel laybye and asked for my money, they denied because I misplaced a receipt. What surprises me is that when making payment for the same laybye a receipt is not needed. Who in 21st century needs to produce a piece of paper as proof of purchase when businesses save details inside computers? I think OK furniture is only making an excuse to keep my money. I only need my money back, nothing more?!