Big wheel spam

I bought to groupon vouchers for the big wheel in the waterfront. When i got there they said only the one groupon voucher works and the other is invalid. I now had to pay double the price! Called the call centre and they advised they cant refund me. Maybe they will review crediting my account. I dont want a credit as i have never felt this about a company before but i will never buy from them again. I just want my money back