Wrong Amount debited

My car is financed by ABSA for the last 2 and half year. They debit a certain amount each month, but this month they debited more money (over 1500) more. i have sent 10 emails to absa, i havent been assisted. i wrote an email to them asking to have my money back. no one from the Vehicle and Asset department has rep**** to my email and even phone me back. I want my money back. i have a budget and by absa taking more money than the agreement they have really inconvenienced me. and the silence from absa speaks volume.