I took my car to a valeting centre, but after collection I found they had broken the electric driver's seat. The spindle is broken due to them pushing the seat over a fire extinguisher that is located beneath itr.

They claim they could not see the extinguisher because of the car mat. They have also blamed the fault on wear and tear on the spindle as a result of the seat being moved over the extinguisher over time.

I have tried to negotiate with them in term of payment to fix the seat, but they refused and have told me to take legal action as they will not pay. What should I do?