MTN refuses to help with account settlement.

I moved to the UAE 13 months ago. Since moving here, I contacted my cellphone provided Nashua Mobile, to find out how to settle my account and stop all further correspondence. At first, I got one or two replies back and then it all went radio silent. After numerous attempts to get hold of Nashua Mobile, I heard via the g****vine that they have gone bottoms up and that MTN will take over all customers. Out of my OWN accord, I contacted MTN to state that I want to settle my account. Basically, I just didn't hear back from MTN. Once in a blue moon, I'll receive an account - which is almost always in arrears - then I pay it. But every time I request to know what the settlement amount is. I just don't hear back from them. Since then, I have received final letters of demand from 2 or 3 debt collectors!! I have emailed them ALL the correspondence to MTN to the lawyers in order to settle the matter and to my utter frustration, even the debt collectors don't contact me back! I've tried calling MTN from the UAE on 8 different numbers and I can't get through. I've sent them messages on FB, but I don't get a reply. I feel like just giving up and not paying them another cent...