Bad service of MTN

I got a mtn contract for R199 per month. It is May month already, I could use my data December last since January I get a msg that number is faulty, I send emails and phone with no response, now the msg is that the sim is not Rica, but I use it for nearly a month already I went to the mtn shop in Uitenhage in the Eastern Cape, the lady struggle and took my number and said she will get back to me, I visit the shop on the 29th of April it is the 5th of May already and nobody came back to me. I think this is absolutely bad service of Mtn.