Unwanted Mobile Service

I bought a new sim card for my old phone two weeks ago, and somehow ended up with an unwanted service - F.M.90

I don't even know what these 5 Baht messages are about - my mobile cannot display any graphics or play mp3s, so I just get a lot of gibberish on my mobile's text display.

Repeat requests to the call center to stop this annoying service just results in more frustration - apparently they cannot cancel it without a contact number.

Can anyone kindly help with a contact number for F.M.90?

Many thanks in advance for any help.