Blocked Hand set

On the 3rd of Feb I tried to make a call and a message appeared say that I was not registered on the network. I then visited the service provider to establish the cause. I was informed that my simcard was working normal and that I should visit Samsung to get my handset repaired. The next day I took time of from work and went to Samsung and I was informed that my hand set was black listed. I then went back to MTN after a long while it was discovered that Telkom had black listed the handset and I was sent to Telkom to enquirer further. Telkom accepted that they have black listed the handset because of nonpayment by Nashua or MTN. I returned to MTN and explained the story and a log was made. The next which was now the 5th I received a call from MTN and I was asked to find the proof that my hand set was blacklisted in a form on and email. At this time I lost my composure and I was given the supervisor who stressed how important it was for me seek this proof. I strongly expressed my view that I was not getting the service I anticipated and that she needed to escalate this matter to the next person in authority and this did not happen until I ran out of airtime from my Vodacom hand set.