Here's my form letter:

Dear _,

I am writing regarding [describe problem].

The appropriate resolution to this issue is [describe solution].

[Usually the solution is cash; if it is cash:] You may credit this to the form of payment you have on file, or by sending me a check at [address].

If you have any questions, you may call me at [phone number] at [time when I'm always free on a weekday during working hours in all us timezones].

I will contact my AG's office if I do not hear back from you in 30 days.

Thanks, [Name]

Mail it.

All state AG offices have a form for consumer complaints on their website. Usually it's very easy to find. Don't overthink it. Mention the letter in your AG complaint, include a copy and the date that you sent it. They will contact the business and start a resolution process. Usually you'll hear back in a week or so.