Should only cost about £40-50 to file with a small claims court and represent yourself in this situation. Which you will get back after if you win (which you should)
I took UPS to court last year as they bashed up a Mac Pro I sold for £1100 and insured for £1000, using them to claim against damages to start with and they refused the claim as they said the packing was inferior for the item (which it wasn't) and they should of refused the item based on this. Took them to court and got £800 out of them for a new chassis £225, my time to fit the chassis and petrol (£300) etc.. Had some dosh left over too.