MTN Blacklisted my Iphone *******y

My IPhone was *******ly and wrongfully blacklisted by MTN on 25 June 2015. The reason given was bad debt. I don't have any bad debt and proved that I am the legal owner of the phone. I submitted an invoice from Outsourance to prove that I am the legal owner of this phone. I have a contract with MTN. My account is still active and I get access to the MTN network if I insert the sim card in a different phone. <br> <br> I suspect the cause to be either a finger fault by somebody entering the wrong EMEI no or it could be sabotage from disgruntled MTN employees. I have completed forms at the Brooklyn service outlet to reverse the blacklisting and also submitted an affidavit. Up to now there has been no reaction from MTN.<br> <br> I can't succeed to follow up or query the blacklisting because their customer service number rings up to 30 minutes without anybody answering the phone.