Debit order going through but money untraceable

Standard Bank is debiting money from my account on a monthly basis for the accounts that I have with them. However, on a monthly basis, attorneys call me to say that my account is in arrears and they don't receive my money. I have been trying to call Standard Bank but every department that I am transferred to, I am told that they don't tell with the query I have. This has been going on for 6 months and I still don't know what is happening. I wish someone could solve my query because Standard bank has been debiting from my account for almost 4 years