Staff unaware of process in place and **** about refund

I unfortunately lost a voucher had been given as a gift from Oyster box. I had made a booking earlier in the month for the day. I advised them before hand that I had misplaced the voucher. They advised it was perfectly ok for me to come on the Saturday and all they needed was my credit card details which they would debit in case they could not find the voucher on Monday, I could pay and all they needed was to confirm the details of the voucher with the buyer and would reimburse me immediately. I ask them to reiterate this clearly as I was willing to wait until my voucher was resolved. They gave me absolute assurance, all they needed was the buyer's details, which was their name, the amount, number of vouchers and their phone number to trace the voucher and I would have my money back within a few days. On this basis I paid expecting them to refund me. It has been an absolute nightmare now. The purchaser confirmed they bought the vouchers and I was a recipient, after i pushed them just to call them as they were not contacting the purchaser. I have had to follow up continuously with false promises of resolve and call backs. Its absolutely frustrating. They **** to me or they do not know their own processes and to date have not resolved the matter. I have even tried to assist them however there is no resolve. Absolutely unprofessional.