Disgruntled customer

I've been waiting to be assisted on a recent upgrade and have not received any response from Mondo as promised neither has MTN been of much help. I was sold something that I was told would work like my previous package only to find out that it doesn't. Been trying to get assistance and I'm being pushed from pillar to post, it's really annoying and frustrating. What about treating the customer fairly post purchase. I get bombarded with your calls daily trying to sell me something I don't even need but when I try to get assistance from all of you it's an impossible task. I've been MTN's customer for over 10 years and the treatment received lately has really been appalling.