Wrong Contract package was delivered to me and I sent it back to Mtn store.

I took a contract phone with a company called rewards that works for Mnt. They sold me a contract phone and i took it . But when they delivered the phone it was a wrong package.I reported it and i was advised to send it to any mtn store . I did that, i sent it back. Now im being billed for this package ********** 117/ ********** 179 and i dont even have the phone or sim cards. Today im busy calling mtn customer service to try and resolve this mess and im being sent from one department to another. It seems no one is willing to assist me in resolving all this mess. I have been holding for 3 hours for retention department. The service is very horrible