Young Joy And Google Service — unauthorized transactions

I am living in lebanon and just got messaged that someone is using my credit card to do transactions on youngjoy. Gbr.. How can i stop this and refund my money? I appreciate your immediate reply before the amount increases...
Thanking you in advance for your prompt help... It will be much appreciated to send me immediately what to do since it is night time hete and i can not get in touch with my bank