Settlement paid - still a balance

I requested an early cancellation of my cellular contract from the customer care department and I specifically requested that the current bill for August as well as September be added on this early settlement figure, the agent Jacqui Mzobe then gave me a balance that was broken down in an email, I then requested a balance on the 11/09/2015 as I was going to settle the next day and wanted to ensure nothing had changed, I then received a revised amount from Ntombizethu Bopela that was similar to the 1st email, I then settled the account and received statements in October indicating that I still owe money, I then called MTN and spoke to Aimee Appolis who requested I send an email, which I did on the 30/09/2015 which had the other emails from their MTN agents showing the settlement breakdown amounts, I cc'd customer care as well, Aimee indicated that it would take 3 to 5 working days to resolve. I am still awaiting feedback and refuse to pay this balance as i don't understand how can 2 agents give me a wrong settlement amount, this figure led me to make a decision to settle and cancel my contract, I dispute this outstanding balance and request that the account is finalised