MTN - the worst service provider ever!!!!

I have never ever received such bad service like i have received from MTN in general. MTN took off a debit order from my mom's account for 24 999.99 and she only has top-up contract with them for +- 450.00 a month. After logging a call with them via the Facebook messenger as call center refuses to assist me as my mom is the account holder (but my mom is disabled at home in a wheelchair) I requested a detailed billing to be mailed to me on the 4th of November to see why the account was so high. I was told it will take 72 hours for the service team to assist. It's now 192 hours & 2 referrers later with still no detailed billing received. (refers no ***; ***) The phone has been cut-off mean time as the debit order was reversed because it cant be this high, but nobody at MTN can assist a person