Poor service provider

I took my contract from telkom in October 2015 and i was paying R150,then i upgraded on the 26th of August 2017 and currently paying R500, I called your call center and i spoke to Simangele and Emirly who both told me that my contact is ending in November and i will be paying the same amount,according to my understanding the contract i have with you its for 24 months,how do i pay the same amount for 28 months?if you were saying i owe 4 months for my old device i would understand.your service is very poor and your call center cant even assist me.