Emails and messages never correspond

I have been phoning Nedbank with regards to my Personal load, They keep on telling me my account is in arrears and the more I make extra payment the more I am in arrears. I have phoned numerous times to find out how i can still be in arrears and they just tell me I missed payment, I know i missed payments that is why I made an arrangement to pay extra to try catch up the payments. The lady i spoke to 20min ago became arrogant and rude telling me i wont admit to missing payments, but she cant tell me why my arrears never comes down.