Not settling the account

On the evening of 20January 2016 I rushed my daughter to the Emergency Room in Mercantile hospital with a gash wound to her leg.The next morning I phoned my medical aid and they ensured that I dont need authorisation as my daughter was not admitted.I left it there and three months later I received an account from the hospital informing that the account was not settled.I followed it up and they informed me that the account was not settled because there was not an authorisation number.How strange!So now I have to settle the account myself.I feel its unfair because basically its my word against them.