Airtime and Data vanishes

As a MTN contract user, yesterday I noticed my balance was 0 airtime and less than 1 MB data, and since am at work connecting to WIFI. This surprised me since I know I had airtime and data, any how i decided to load airtime and converted half of it to data. Few minutes after I noticed am back to 0 airtime and data gone. I called MTN to inquire about this usage and I was transferred to one department to another, and later told that am subscribed to something, and given steps to resolve that, but then when i follow those steps. Am being prompt that am not subscribed to anything, with patience I call 808 again and this time an agent stated that am not subscribed, but to resolve my case I asked for a data billing report and he says I should call after 2 hours since MTN system is slow and take that time to pick up my usage and waiting after 2 hours to be told that I should wait for 13 days, just to know what happened to my data and airtime. Now am even sceptical to load airtime, am quitting MTN, it sucks and its bad network along with its service....