I am deperate

I have been trying to sort out a query on my MTN Data contract . I have spoken to 4 different people over 6 calls lasting over 30 min each promising that they are logging a call and that someone will come back to me within 2-3 days but without any response. I phoned to load a once off 5 GB data bundle on my account on 12 October and to have my account unlocked as I have used up my 10Gb package. After multiple calls the data bundle has still not been loaded and I have been charged out of bundle rates. I followed up again on Friday and (now in tears with frustration) spoke to a Manager who promised to sort it out and get back to me within an hour and also mail me so we can talk directly re updates. I have left 2 messages for him but have had no email or response three days later. I feel completely helpless! I have all the reference numbers, call records and the names of everyone I spoke to. I tried to close my account last week but still waiting for a call or mail from retentions to even get this done. Ironic - I cant even get someone to help me close my contract. After 10 years as an MTN client this is it. Can someone please call me to close out my account.