Not receiving the data I paid for

After MTN took 7 days to fix my line that they broke, I am now not receiving my full data allocation. For the last two billing cycles I have received 10gb less data than I am supposed to, I called on the 2nd of January, and was told I will receive an escalation, nothing was received. I called on the 3rd of January and spent an hour on the phone explaining the issue again, I have followed up on the reference number received again today 13 January and was told the escalation was to the wrong department and I they are escalating again to another department. I've now paid for 2 months for data which I did not receive, I want my data and I want a credit on my bill for the data for December which I paid for and didn't receive.