ATTM*188060752277GLR 800-331-0500 TX

I think it's your AT&T phone bill.

In my case, the ATTM was the AT&T Mobile (cell plus ipad) bill autopay on my Visa and the numbers that followed it were the account number of the charges.

It's At&T bill

AT&T Wireless

For me, this turned out to be AT&T "session based" (i.e. non-contract) wireless.

This ATTM Georgia is a scam charge. Go to your Attorney General of your state and file a complaint.

Definitely a scam. Received the same message, unanswered calls, four times from four different 800 numbers telling me to log onto a site for free $500 to $1000 dollars and adding that AT&T "cares about you." Here are three numbers I saved, (800) 331-3015, 315-1059, 271-2049. One number is a Dude Ranch, another a hotel in Michigan and the third something Chinese.

another of the 5000 variations of Att secretive charges.....call 800-288-2020 hit zero a few times and you'll wait a bit but a HUMAN will answer. :)