DATA DISAPPEARING

I have been having issues with my data since the 18 Jan 2020 yo date...I made several calls to Mtn, all they did is to give me instructions to data saver, data restrictions etc on my handset. I did all that and every time i test by buying data my data still disappeared. I dont think the problem is with my phone, i have been using the phone with those settings for a long time with no issues, WHY NOW????. No one suggested to log an incident to look into my grievances and investigate why data keeps disappearing from service provider site, check if there where no changed done on my account. I AM SO DISAPPOINTED WITH THERE SERVICE, I HAD CONTRACT WITH MTN FOR MANY YEARS, DIDN'T EXPECT THIS KIND OF SERVICE. I lost almost R500 in a week buying data.