Worst accounts/ finance department

Absolutely the worst customer services I have ever received from the finance/accounts department. Have been logging complaints for the last three months as they are invoicing and debiting my bank accounts with the wrong amounts. Although they acknowledge the fault on their side no consultant are able to resolve the problem, only making empty promises. Don't even try to get into contact with any supervisor or manager, they are never available. No wonder there are almost 2500 bad reviews about this company.