Wants me to pay unrequested laboratory test

My son was admitted at medi-clinic Lephalale , t/d 16/07/2014 and the Doctor requested x3 blood test on the lancet laboratory form. And I have a copy of that Lab Form and it clearly shows only x3 blood test.<br> So because those test that the doctor requested are very cheap they added their own additional x2 tests that are very expensive, because I'm using medical aid they thought maybe it was not gona be noticed. So my medical aid(Bonitas) noticed it and rejected their 2 additional test and paid the x3 test requested by the doctor that appears on their lab request form. So now they are forcing me to pay that money. What should i do?