No internet connection

I decided to give MTN the benefit of the doubt, despite all the terrible reviews, and how I wish I had listened! I am terribly disappointed in MTN. I paid for a month-to-month LTE package. It got delivered on the said date (25th of July), however it hasn't connected at all since I've received it. I have followed all of the instructions as per the manual but the sim card is still not working. I can't get a hold of anyome who can help me. I don't wish to continue with MTN at this rate. Never again!