No service delivered

Mtn is the worst service provider ever, on the 20th of September i bought 20gb once off mtn sim card from their website, paid through my banking app and the sim card was delivered on the 25th of September. After activation through customer service I discovered the data was not loaded, I have spoken to many agents almost everyday over the past month to try and get assistance but non of the seem to care, I have tried many methods to get their attention including whatsapp, Facebook and email but I haven't received any feedback whatsoever, I'm really disappointed considering I have been a customer for years.