Unknown account charges

DRI.AVG charged my amex account for $99.99, I did not purchase any avg.  Do I tell Amex that the charge is not accepted or what?

Hello John,

We'd be glad to clarify the charges for you.
The charge of $99.99 wasn't found on your current account of AVG. However, we have located it under other e-mail address of yours. We have sent an e-mail for you and revert to us with the requested information to verify your account details and proceed further.
Thank you.