Poor service

I’m highly disappointed with Mtn i have sim data contract its been more than 3 years, i phone them to renew my contract since i was not happy with the data they suddenly change my deal without my consent as from 2020 November i used to get 160 data and this year they are giving me 20GB daily and 20GB nite. I requested to do an early upgrade on the 17 of May i spoke with an consultant and we had an agreement boom today as the 12th of June my data has not been loaded, i called them they never told me what was the problem. I dont know how they work. M so disappointed i wish to cancel everything