medical fees still unpaid

I gave birth on the 08th of June 2015 at Lenmed Hospital. Authorisation had been received from the medical aid, prior to giving birth. However, the gynaecology fees have still remained unpaid, and I have now been handed over to attorneys for debt collections. I have been contacting GEMS since July 2015 to follow up on the payment, as well as get a reasonable explanation as to why the fees were not settled, which I still have not received. I have reference numbers or each occasion I contacted GEMS, as from July 2015. Now GEMS has informed me that it is a stale claim, and can no longer be settled, without offering any alternatives or suggestions to solve this problem.