Frustration with MTN blocking my data

Since 2 weeks ago, I have been receiving messages from MTN that I'm out of data, whilst I still had ± 40 GB available. Since then I have been trying to have the issue resolved, but with no success. I've made 18 calls already, and then I'm being told that everything is now working, but it's not. I cannot use the data I'm paying for and MTN doesn't seem capable or interested enough to sort out their own mess. I am frustrated and don't know what else to do, because my only avenue is their customer services. Reference numbers SMC/*** and REQ***.