Bad service

I am at Ayanna stores,I laybeyed items and fortunately items were on special then I bought cash those items that were on my laybye. I asked for refund because I lost slip the Management is exchanging words for not reading slip ,I want my refund they to give me voucher of which I don't need it.i want my money back but I lost my slip.so why they did not emphasize that if you lost their slip they don't refund you they give you voucher even if you give them your ID documents. I do not need their voucher they were suppose to make me aware of the matter