HORRIBLE SERVICE !!!!!

I withdrew money from my momo account on the 2nd of November and I have not received a withdrawal voucher to date. I contacted the MTN call center, and they assured me the matter would be resolved within 72 hours. To date, my issue has not been resolved, and my money has not been received refunded. I have made several calls to the customer service center, but no one seems able to assist me with my withdrawal voucher and yet MTN expect me to pay an interest on the money I have no received. I do not advice anyone to use the Momo service rather try other service providers not MTN.