Hyperli too arrogant to accept their mistake

I purchased 2 Hyperli vouchers in December, one of which was a Xmas gift. When trying to use it the vendor refused to honour it as they cancelled the agreement with Hyperli and Hyperli should have removed the ad basically falsely advertising it. When I requested a refund they refused to refund me and gave me a full credit forcing me to buy through them again which after this incident I did not want to do. I was forced to use their platform due to their false advertising and misrepresentation and they never even offered an apology for their incompetence.