MTN rips you off

Every 2 years I upgrade my contract after Black Friday. Every year MTN ends my contract on the 13th of November and charge me full price for the month of November, until the new contract becomes effective. When I question this I am told this is how it works? How can MTN make we sign a 2 year contract but end the contract early and bill me out of contract rates for the month of November. This is such a con and a *******. So not impressed