Bad Service

Finchoice called me 11 times (not even counting the dropped calls) already for an outstanding amount on my account which the debit order went through on time as arranged. After 6 calls I have made to their customer service department they could not manage to resolve the problem. I had to email them my bank statement as proof of the debit order that went throuth. To date no positive outcome. But still they keep on calling me. Am I dealing with untrained staff members who are unable to resolve a problem.