Account handed over while I have a current account

I have been harassed by debt collectors stating that my mtn account is handed. I have a. Current contract with Mtn and they are debiting my account every month and have never defaulted on my account. Called call centre to check the status of my account and I was advised that everything is in order and my account is not handed over i have been trying to call their legal department its been a week now and know one answers the phone.I have been a loyal customer to Mtn and really disappointed about their services lately,was looking forward for an upgrade but this silly thing definitely makes one think.Can someone at Mtn legal give me a call to sort out this mess as my credit profile is affected by this mess!!<br>