Account not submitted to medical aid

On a couple of occasions we have used the services of Dr Schutte Inc for X-Ray's. We don't receive the account and assume the bill is sent to the medical aid. A couple of months later you receive a letter from Redelinghuys Attorneys for outstanding account and legal fees. I understand you should not assume that the bill is sent to your medical aid and follow up, however they are the only doctors that we have this problem with. And funny enough most people in Randfontein have had an incident exactly the same. Why like any other company would they not send you an account 60 days overdue or send an sms to remind you or advise payment was not received? Something just does not seem right with these two companies as if they work together...