It's not the FAA or your local AG. It's the DOT. The law is Unfair and Deceptive Sales Practices. There is a formal complaint you can file. If you want the DOT to actually investigate it you'll likely need a letter from your Congressperson or Senator asking the DOT to look into your complaint.

The fare class issues are an issue of the partner carrier and not DL. However, DL has the ability to disclose at time of sale that the ticket doesn't earn miles.