ROBBING OF MY DATA!

So today at 08:52 I received a message from MTN that my 1GB monthly data has been loaded, at 09:54 I receive another message from MTN telling me that my 1GB bundle has expired? ***? I did not even use my phone? So can somebody please explain this to me? I tried calling the help line, either being cutoff or being put on hold for ever! I have been with MTN for more than 20 years! me thinks it's time to investigate another service provider, who will NOT rob me of my data that I pay for!!