Bad service

I am wringing this with a huge disappointment, I moved banks, I have a vehicle finance with Standard Bank and saw it as a good idea to move to Standard Bank. I have moved my salary to Standard Bank and moved my motor finance debit to Standard Bank, however for some reason they are unable to debit this instalment and keep threatening me. I have made multiple calls and even went to the bank but no one seems to know what the issue is, I keep getting smses and phone calls that my Acc is in arrears as though it is my fault.