[Resolved]  Royaloak Furniture — hydraulic issue

I had purchased royal oak double bed on jan 7th 2017.
I used the bed storage first time but found that the hydraulic was not working after it fell on the hand soon after it was open while keeping things in the storage.
The problem was attended by the service persons. It was told we need to replace the hydraulic & it is chargeable.
I don't understand at that the hydraulic which was provided at the time of installation was a defect piece, why are they asking us to pay for it.