Misrepresentation of contract and failure to respond

I upgraded my contract in February this year to a contract with 50GB per month in data. This was done on a call with MTN and I was told on the call that any unused data would be carried over to the following periods.

On the first month after this upgrade, I noticed that my unused data had not carried over. I contacted MTN on Twitter (reference ***) and despite a month of engagement and promises that my complaint had been escalted etc, I have received no meaningful feedback. I will be opening a complaint with the Office of the Consumer Protector next week.