Being Incorrectly Billed

MTN South Africa - I signed up for a MTN home router data 1T contract for R1059 per month in October 2021. My first month I was prorated twice! And from then on I have been billed over R1521.55 every month! I have called the Call Center numerous times to get this sorted out. I have been "fighting" this for 3 months now. And all I have is numerous reference numbers! Not to mention all the airtime I have used to try & get this sorted out... They now owe me money but if I don't pay them every month then my data is cut off... This is ridiculous... Is there someone that can please help me?...