Worst customer service experience ever!

I have never experienced such poor customer service.

I got a new contract with MTN through Mondo and they sold me the wrong contract. I've been waiting for them to cancel since December and I'm still being billed for a device I don't even have!

Every rep I've spoken to tells me they've made an urgent escalation but I still haven't received any feedback. You'll think they are as enthusiastic as they are when they sell you the product but NO! Even the Manager Jason seems to not care at all because after 3 requests to have him call me back, still nothing. I'm going on month number 3 and my blood is boiling!!!!