Worst customer service from proforce accounts department

I am getting the worst customer service from Proforce Security. I recieved an email from them indicating that my debit orders from 2016 have not gone through for over R6000. I’m trying getting them to check their accounts has been a night mare with several follow ups on a daily basis. I have sent proof of the last three deductions which are readily available. There is no effort to check their information , they do not call back, one email I recieved from the indicated that they have no will to even check. Getting statements from 2016 will cost me an arm and a leg and I can’t have that expense because of their incompetence and appalling customer service.