Mobile data - for what? It doesn’t work!!!

At the top of my phone it shows full reception bars and “5G”, but the connectivity/reception is terrible! I can barely do anything with mobile data anymore. I get 20+ GB’s every month which I can’t use because it DOES NOT WORK!!! Everything is slow, YouTube videos barely load, social media pages don’t refresh, streaming services don’t even work… it’s absolutely ridiculous! I saw a consultant at a branch and she said everyone’s having the problem, so there nothing she could do… really MTN, really??? I’m in Kempton park and this issue has been non-stop for a few months if not longer…