INACCURATE Blood results given

I did a blood group test at Dischem Cresta May 12th 2016 for my new medical aid and the result was B+. I did another one as requested by my Doctor last week August 12th 2017 at Clearwater and the result was O+. Obviously my blood hasn't and would never change. I had to go to the lab to get a more accurate result. I do not understand why I have had to do so many tests to get an accurate one. It's completely unacceptable especially because this has to do with my health, it affects me directly. What would have happened had I gotten a transfusion of a wrong blood type. What's worse is that the Dischem team (Cresta Clinic sisters) have not been helpful with this. They are taking this whole thing lightly. I phoned them today (17/08/2017) to query the test. Sister Koury who I spoke to was rude and told me off. Dischem is a pharmacy I love and trust but after this drama, my family and friends are never going back for anything.