MTN's disgusting customer service

I have just recently taken out a contract out with MTN and was given a once off data bundle. On the MTN app it shows that this is meant to expire on the 11/12/2018. On the 15/11/2018 I had around 29 gigs of data left. This was then taken away.When I had called to why this has happened i was informed that this has happen to a few members and that the data will be returned within 24 hours.

I had called to the call center to find out why it was returned as yet to be told that MTN had made an error and load the data twice and that it was removed. I had spoken to their line manager to find out why I was not informed of this.The previous agents that I spoke to have not been leaving notes when I have been calling in and when I call in now the staff just place me on hold and forget about the call.I find this type of customer care very disgusting. I was promised a call back from a manger of MTN within 24 hour from Friday and I am still waiting. It seems to be that no one at MTN not even the managers provide members with good customer care. This is very disappointing that customers experience such poor service.