Grinning Corpse

There must be a clue for how to solve this cypher, what was the name of the person using it again?
The user Brian is messaging is named Atoz, or A to Z. If you change all the letters to their reverse in the alphabet (A becomes Z, B becomes Y, and so on) you should unlock the secret!

Brian is getting some very specific targeted ads. Is there any way to investigate that further?

Go to the web address in the ads on the side of the printed out Blueit posts.

There must be some way to figure out what radio stations Brian was listening to…better go check everything a little closer. P.S. There’s two different stations to find!

The back of the receipt from Brian’s glovebox gives us our first station: 99.2.  The second one can be pieced together through close inspection of his Tittle Tattle posts. In his first picture, the advertisement behind him gives us the first half: “10”, and his final picture finishes it off with “2.9” giving us the full morning station of 102.9