Airtime not received - Poor Service

I have a cell phone contract with this company. I went in arrears and the sim card was blocked. I then started paying the installments on a regular basis. I did not receive any airtime while the sim was locked nor did I receive the airtime after the sim was activated. I have spoken too so many people since March this year to find out when that airtime will be allocated to me as I am paying for something I did not receive. Very disappointed in their service as this is *******.