Lack of Service

I have been a loyal MTN customer since I got my first cell phone. I am slowly losing my patience with MTN Call centre. I have tried for almost 3 weeks just to get my March invoice. A service that I pay for. Firstly when I have called the Call Centre on average I wait for about 7 to 15 minutes to get the help I need. And the 15 minutes is only because I dropped the phone. How hard can it be to get an invoice? I have spoken to numerous consultants who have promised to send it. It also seems that if you become frustrated and share this frustratin with the consultants, they delibertaely put you on hold sothat ater 15 minutes you have no choice but to drop the call. Oh they sent invoices