Charged for a purchase I have not done

Hello,
My credit card account has been charged for a purchase I have not done, at least consciously. I sent an email to DRI AVG TECHNOLOGIES via the website platform. I received an automatic reply stating that they would contact me but no email so far (even in my junk mail box).
I recall that I made a purchase one or two years ago, but I had selected the option not to renew the purchase automatically at the expiration of the annual period.
I have tried to find the order number via DRI AVG website (with my name and the four last digits of my credit card) but no order was retrieved. 
I'm a bit puzzled in front of the complexity to get in touch with the company. Shall I just ask my credit card company to reject the payment?
Thanks in advance for your guidance.

Hi Jean,

We'll help you to locate the charges.

I have sent an email requesting additional information as it is not advisable to get account information in public post.

Please check the email and revert back for further assistance…