Cartrack making clients pay costs for correcting their debit order errors!

Cartrack decided they wanted to debit a lesser amount from my bank account and have the audacity to harass me about an outstanding amount like its my fault they didnt debit the full amount, the money was right there in my account. What infuriates me the most is that they want to charge me for sending me a new debit order mandate like the whole issue was my fault. I have reason to believe that they make money off of these "errors" that they make on purpose. I will not pay for a debit order mandate because its not my fault you didnt take the whole amount. Cartrack stop imposing the costs of correcting your own errors on the clients!!!