UNABLE TO RECEIVE CALLS SINCE DECEMBER!!!!

I took out a contract with Altech Autopage in December, after a week or so I discovered that certain numbers could not get through to me, when they called it would say the number does not exist... I called the shop (Altech Autopage Balito) and informed them, they said I must try the sim card in another phone, and try another sim card in my phone ... I eventually went into the shop and did the same process. I was informed that I needed to buy a new sim card, I did so...... so after all the calls, and trip to the shop and buying a new sim card I still have the same problem... I contacted the help desk they sent me an sms that they handling my query....BUT nothing has been done... <br> <br> I need my money back for my simcard and my number working correctly as it ought to be...<br> <br>