Not Being allocated airtime i am paying for

in November last year my contract was transferred from Nashua mobile to MTN, since then i have not been allocated my R200 airtime per month as part of my contract which i am paying for monthly. i only picked this up last month. i logged a call with mtn on the 3rd of August about this, the person at the call centre confirmed this. i have made numerous calls to follow this up, and they keep telling me to wait 7 days, right now i am still waiting for a response, and for my refund, as i have been paying for calls when i shouldnt have been paying for them.