Extra charges

If there was an option not to give any star I would.... MTN is nonsense. I was upgraded on the 19th of July for my router I agreed, this morning I get an sms that my bill is R1700 extra when I call the upgrade was not done and I'm month to month ..... WTH a person should just cancel this is nonsense 😡😡😡😡😡😡😡😡😡😡😡😡😡