I do as Lori S does. It isn't only Northcott. This is the one main reason I don't buy pre-cuts, plus you're paying boocoo bucks for them cutting them and they don't really seem to care.
I would send or take them back to the store, let them take care of Northcott, regardless of the fact that you've already cut them. You have paid a great deal of money for the pre-cuts the least they should be able to do is to cut them accurately.