Useless accounts department at lancet laboratories

So I have been in hospital in feb and had some tests done by lancet laboratory’s. The accounts department did not submit my claim right to the medical aid so not all the payments where made so after that I had to do there jobs by contacting and email the outstanding petuholagy request notes to the medical aid, witch they are still denying that they did anything wrong so part of the outstanding amount was settled, then yesterday I received a email stating that I still owed them money so I queried this morning just to find that they did not send me all the outstanding requests notes now I have to go through this 2 week nightmare once again, I am really dissatisfied with the pathetic service that I have received and that I have to do there jobs cause they have no clue what they doing also the rude and unhelpful attitudes of the accounts call center the service is less than standard and I will always avoid using lancet ever again.. also I will not be liable to pay any money for you mistakes this is not how you run a business really unprofessional..