I regularly shoot Provia 100 in 6x6 and some of my very best (my favorites at least) were scanned on a Nikon 8000 and printed on a lightJet at my local lab. I was in awe when I got my prints back--very very impressed and thats saying a lot as I'm very anal about print quality. Blame your lab and request a reprint!!!
You bring up a good point. The quality of the scanner matters TREMENDOUSLY.