I got given a gift card with around 6 months credit on it. I used up 1 or 2, and last week suddenly the credit disappeared. I reached out through their chat bot

I got given a gift card with around 6 months credit on it. I used up 1 or 2, and last week suddenly the credit disappeared. I reached out through their chat bot, raised a ticket and have been emailing them daily. Nothing. Absolutely not a word. Unfortunately I dont have the option for a charge back.