"Bad experience when bring my baby for blood tests."

I brought my baby (around 6, 7 months) to the Pathology in Knox Private hospital to take blood to test the iron level. Firstly, my baby was very calm and very cooperative when the nurse tries to take blood from the vain in the arms. Not much blood taken so they decided to do a small cut on the heel to squeeze out the blood. My baby started to feel pain and cried. I did feel the nurses were confused when they saw the baby was in pain and cried. But I kept very calm to calm my baby down and told the nurse to take enough blood. When they were still hesitating and questioning each other whether there was enough blood taken or not, I did emphasize and repeat to them many times that please be calm and take enough blood as I didn't want my baby to go through a painful procedure another time. Finally they told me it was all good, I could leave. Before that I still asked them one more time, was there enough blood or not, did they need my help to get it, they seemed to hesitated, they said no, it was alright. We went home and a day after, they called me to tell me to come back the the clinic as they didn't take enough blood to test. My husband needed to take a half day off to bring my baby to hospital, pay expensive car parking fee there and then my baby already in pain from arms and 2 heels. I have no idea what they thought, are they professional? Should I be angry in this case? Whom should I complain when my baby blood test weren't done correctly?