printing

So..went to print my cover and concertina today and everything went well except there is this faint purple line over the chest of my model on the A3 poster - I got it reprinted like 3 times and it was still there, so this is what Im stucked with to hand in. It is weird because on my A5 cover, there is no line over her chest although it is scaled down from the A3 file. The conclusion is that, it is from the printer's paper and I can't do anything about it - this includes the minor scratches on some of the paper aswell (they refused to reprint it for me). I did considered going to print the poster somewhere else but then the colour would differ to that on the consantina and that would be equally bad. Although, I am happy with my finished outcome, I'm still dissapointed that the printing didn't do my work justice as it looks so so much better on the computer! Hopefully Amy understands this circumstance :(