Who called from 8012222357

I keep getting spam texts at 20c a piece from 11-801-222-2357 which could be in yugoslavia

Keep getting text messages telling me to reply if I want them stopped.

I keep getting a text mesg from 801-222-2357 and all it says is to text if you would like them to stop, i have texted stop to them several times..

I keep getting texts from this number saying that if I want them to stop, I need to reply and they add "(charge may apply)"

I am getting the same text message.  i want to stop this once.  i send MC=1 but don't work. please tell me what to do?