Extremely Upset and disappointed

I purchased a deal online, however an agent called me and wanted the deal. Mtn did not contact me and no deal has gone through...on my upgrade. From my side I purchased the phone online but now they telling me I can't have the same deal. And now I must lose out because of their negligence. And the worst part is no one can tell me what happened and assist me. It must keep getting escalated, that's all they do escalate...escalate and still nothing gets done! Also they have no support for their online store??? Really Mtn?? Because whenever I speak to the agent they say they cant assist because its online...oh my word! What service is that?