MTN contract

No matter how tempting it is never ever take a contract phone with MTN, you will pay ridiculous amounts that they can’t explain. My contract was R399 it changed to be R408 I ignored it, the last two months I have paid closed to R2000 when I ask them they keep on telling me they will contact their billing department and they will contact me. They have never done that. There’s no invoice sent to me as I requested the breakdown of the amount they claim I owe them.