irritated and furious

My mother was due for an upgrade with MTN. Last week Saturday we went there and they couldn't help her because they had a system problem. She was advised to come back on Monday and still they were unable to assist because the limit for the phone was apparently not set....I called yesterday for the status of that contract and Shawn said he was gonna escalate the matter and he promised to get back to me but he never called me. Upon calling him AGAIN today he claims that he still doesn't have any response from whoever he's supposed to get a response from. What now? I told him to cancel that contract because I'm fed up with MTN. I'm seriously disappointed because I've been using MTN for years and I don't wanna change networks but I'm tempted port to another network. I am very furious with the guy's attitude....He needs to change it.