Help gel nails gone a funny colour!

[Jemster]

A week ago I had gel put over my own nails. I've noticed the past couple of days they some have gone a funny colour, with a bluet tinge to them. I know it's not my actual natural nail colour as a bit of the gel peeled off and natural nail is still normal pink colour.
It looks like the gel varnish has got dirty but how do I clean them up? I'm not happy as they cost £40 and have only lasted a week. Should I say something to the salon?

I was warned about this when I had gel nails put on - but unfortunately I can't remember what caused it.

I think the girl said it was the nail varnish coating the gel rather than the gel itself and it could be removed and reapplied - but please wait until someone who hasn't had a couple of glasses of wine and is half remembering a conversation from 6 months ago comes along.