I asked them to help me fix the issue of data plans disappearing from the app and ussd options

I asked them to help me fix the issue of data plans disappearing from the app and ussd options.The first agent said they’ll reset my settings and told me to switch off my phone for 10 minutes and said I should call if it doesn’t work.It didn’t work,I called again and the second agent said there’s nothing he can do on his side and that he doesn’t decide what the system does. I’m so disappointed because I now have R350 airtime that I cannot use . Can they atleast use my airtime to credit my momo app because that data option is there. My app doesn’t even open now, not even the Momo app. I don’t know mtn like this and I’m considering leaving now because what do you mean the data option is there then once I recharge with the amount ready to buy, it disappears and only small and expensive data options appear.