MTN and Nashua Mobile

I have had a contract with Nashua Mobile since 2009. I kept on getting contacted by MBD regarding outstanding fees on my MTN account. I told them that my account was not with MTN but dealt with Nashua Mobile directly. I was then told that Nashua Mobile has closed down and the account has been handed over due to none payment. The account debited and the debit was not switched over when MTN took over. There was no communication sent out to me regarding the whole issue of MTN handling the accounts. And now they were not debiting as per arrangement with Nashua Mobile and the account is in arrears (R7K). This is such a disappointment that there was no proper handover process from Nashu Mobile to MTN and this is now affecting me. I need a solution as I am not prepared to pay for someone else incompetence in arranging the necessary details for a smooth transition. I am really not an MTN fan right now