Bad Service from Call center agent

I called in Mtn call center due to the airtime voucher that vanished without being used on my phone. This has happened before. The incident happened on the 5 Dec 2015. I just loaded r10 airtime to gain access to my flat however the airtime just went from R10 balance to R0.00 in a matter of seconds. The very rude Siphelele (customer champion) didn't listen to what i was telling him, he kept on saying i used the voucher when i tried telling that thats the second voucher that i had to buy after the 1st one vanished instated he choose to hung up. I have worked as a call center agent and I know for a fact that it is unacceptable to hung up while the customer still talking unless he or she is using swear words which I was not doing. I've been with Mtn since I've had a phone(+10 years) and i have never had this kind of problem before. i will not call in just for fun. Maybe he has nothing better to do but be rude to customers then maybe he choose the wrong profession. THIS WAS THE MOST DISAPPOINTING AND UNACCEPTABLE BEHAVIOR.