MTN Pathetic service and billing jargon

I am being billed for an amount double than the contractual amount that i have agreed to with NO EXPLAINATION. Apparently it is a SPEND LIMIT which i have used that i have no idea about. The MTN is absolutely cumbersome and terrible to use, furthermore it is impossible to pick up the phone and talk to a human due to the dumb and useless 135 contact number. I have attempted changing the said spend limit to purchase data/voice but the app ALWAYS ALWAYS ALWAYS says something is wrong, so it never works and i use my immediate cash through my banking app to purchase. The offers advertised on social media or even on the dumb app is never available to me, so what is the point. i do not want to be called by mtn, i want a detail statement that shows why i was billed the amount i paid. DETAILED. The term spend limit and bill limit are very confusing to me and i dont think any other provider uses this bull****. please send mentioned statement to ***. one last thing from a consumer is to simplify the app and make it useable, it is USELESS and seems like a 5 year old developed it.