Settlement Amount Drama

I have been calling all day to get a settlement letter/amount for my vehicle finance with zero assistance, I kept on being transferred from pillar to post and I was told that the person who is dealing with my account is on leave. I kept on calling until I was told that I will get the settlement amount within 24 hours. I now have the settlement amount and have called back Toyota finance to explain the amounts and they have failed to do so. I was then trasfered to customer service where I was partially assisted but my request was still not met.

I requested that I pay 80% of the settlement amount,I then asked for a payment arrangement to pay the balance over in a period of 4 months so that I don't pay the interest rate that I am currently paying? I need my interest to be re-calculated, that's all I am asking form.

Can someone help?????????????????????????