hi m8,seems a common problem.When the bodyshop under took fitting my v2 spoiler i didnt expect a call saying can you pop in we have a prob.
well to cut a long story short they had a windscreen guy cheese wire the o/e spoiler off and he had caught the edge of the boot lid with the tool.The bodyshop wanted to charge me but i told them i was not paying for there mistakes.If they sub let part of the job it was down to them.Anyway the job was completed and on collect the bill was as it should be.
hope this helps m8.Stand your ground and hopefully you ve not parted with any cash yet.