complaint closed with out being resolved completly

i have lodge a complaint with mtn on the 12/10/2015 with ref no *** mtn came back to me saying that they have done the upgrade now however my money for the 4 months over charging was not yet refunded to me, i called them tonight to ask what is going on and i was informed the case was closed there was no request for a refund but in my first complaint it was clearly requested and also from the branch that opened the original case, now i received a new case number informing me that this will now again take 7 to 21 days ne case number req ***. i feel its not fair as it has been going on now for 4 months and i have signed a contract with them for that package 4 months ago already as has been informed that day that my account upgrade was done. can mtn please sort this out asap and please can they call me not just send emails i will forward the person the original letter and complaint but i do not except this matter to only be resolved in 7-21 days