Received 100 text messages from debt collectors – Is this legal?

Wow. 100? It what time span are we talking here? Off the bat they can't cause you to lose money by charges made, so if you pay for each text (ouch) then they are in violation of fair debt collection practices act (FDCPA) 808.5.

Have you had any contact with this outfit? Have you returned any of the calls?

They may be in violation of FDCPA 806.5 in causing your phone to go off, but it depends on the time span, though 100 is still ridiculous IMHO.

So who is the debt collector, what is the debt, what have you paid on it, when was the last time you made a payment and finally what state are you in?

With more details about this we can better help you.

the TCPA may apply

Sounds like a major violation of the FDCPA.

Yeah. I was hoping they would come back and give us more information because it looks like they have this company by the danglies.

It is an unregistered guest....they almost never come back.