I mean, if nothing else, it sounds like she's stealing from the company. If I understand it right, she's getting paid for 8 hour shifts without being there for 8 hours. That's a major, MAJOR offense. I would be surprised if she wasn't immediately fired upon investigation of that allegation.

$1 You may do this anonymously or not. Make sure to include as much detail as possible.

Go above your SM

Yes. You can file a complaint against anyone (even a customer I believe).