Quad Test

So I got the results from my quad tests except that baby had a 1 in 6 chance of having downs. Later that day at my dating scan they said she was measuring large. Here we are 2 weeks later and they have confirmed that my blood tests contained errors!!! I am livid. How do you screw up history of down syndrome in the family?!!! They told me it was inputted that I have children with downs already and I only have one child who does not. So I'm worried now that there are more errors on my blood work that no one has found yet. They said she still has a high risk (3%chance) for downs and I have an amniocentesis scheduled for next week but I am going in there without the trust I should have for the system now. 
Do any of you ladies have experience with this?