Bad response from mtn and 3rd party companies

Now i have spoken to mtn direct and there retentions department as well as rewardsco and mondo online on why there is early upgrade fee on my mtn contracts that im trying to cancel because the mtn app says that a upgrade time is available and now im still waiting for a answer of why i should pay R1700 for something there app says. A policy change without consulting with their customers that you can only upgrade on contract end. Sorry not accepting your mistakes after how many calls and emails to you MTN i still do not have a answer