Bad service from Credit Intel!

A blood test were sent to the medical aid with the wrong membership info. The account was handed over to Credit Intel. I try to sort this out for 8 days now. Just to get a invoice for R9694:00. The blood test were for R2111:00. Patience try to tell me that i must pay the amount 4 times + 4 times there fees. And that i should remember that she is from Credit intel. The more i tell her how could i pay the same invoice 4 times and 4 times there fees, the more she told me i owe them the money. ***....... who are they in controle of a problem like this if they do not understand what it is i want her to understand.

Who out here can help me in this regards. Credit Intel do not understand at all.