I forgot to cancel my Tastecard trial and lost half my allowance.

Hi, so I visited London from India for a summer course thing and my parents got me a tastecard trial so that I could dine out if I wanted to for the two weeks i was there. Well, I didn't do shit with it and left, but I completely forgot about it. Then today, some 3 months after I left London, they charged my credit card and I lost half my entire allowance, which I had just received (30 pounds is a lot of money in my country). I tried contacting the customer service and they send me an email saying that they'll get back to me within 5 working days. Is it realistic for me to expect my money back? I'm def not going to London anytime soon so this is practically useless for me.