Authorization without any knowledge or consent

I am absolutely appalled with service from Lancet. My 2 kids were in hospital to which they had a BIO Fire test done.I never knew that medical aids no longer cover the BIO Fire test even though this was in hospital. After speaking to my medical aid they assured me that Lancet was well aware of this and that they should have informed me before doing the test( Which they did not) now i'm left to pay the bill for something which i should have had a choice to make, as the BIO Fire test is just to get results in quicker which was not necessary at all. I find this unacceptable that they did not inform me knowing this and expect me now to pay the bill!!