First off, chances are you were NOT hacked.
This is a common social engineering attack designed to trick users into a knee-jerk response of '**** no! I didn't make that charge", and so you rush to call the number which just happens to be a scammer who will do their darnedest to suck every dollar out of your bank account under the guise of either 'securing your system' or needing your bank account details to 'initiate a refund'.
DO NOT RESPOND - or if you do, send them a snarky message telling them where to stick some sharp pointy object.
If you're really concerned, check your bank account for unexpected transactions - if it were a real charge it would be listed there, and then contact your bank's fraud department for help, but the chances are this isn't going to be necessary.
These scammers send out millions of such messages hoping to catch the 0.1% of people who reply, in the hope of getting 1% of them to actually fall into their trap. It's a numbers game, don't be on the wrong side of that statistic.