Absolutely shocking service

I mistakenly paid for a voucher for two extras when i booked my holiday in December. I only wanted to buy one. I have tried for 4 months to get a refund but nothing. I eventually went on holiday and wanted to use one of the vouchers and then I get told that i don't have any vouchers, so I had to pay full price for the service. I still haven't had any response from them regarding a refund. When you call them, they cut you off. I've asked for the MD's name but this seems to be a big secret. If management are not prepared to assist me after being a member for 20 years, they don't deserve to be in business!