Unknown credit card charge by Avast

In my last credit crd bill i found a charge of 93.99€ by Avast. I do not remember if or when i subscribed. How can i contact Avast to stop this charges or to cancel any subscription related to my credit card? I tried the website but since i do not have an account, i cannot find any way to communicate my problem.

I tried calling but the only number i get is a US phone number and since i leave in Greece is too expensive and the waiting is over 5 minutes.

If anyone knows anything that might help me pls let me know!!!