The insurance coverage after the damage of a warehouse

A couple of years ago, I rented a space in a warehouse (not the whole warehouse) to place my business items. However, the warehouse was hit by floods in Jan 2020 and my items were fully damaged.

Since then, they keep saying that they are not responsible but, 'by luck', they did have an insurance policy that is willing to cover 1/3 of the cost of the goods.

I don't have a signed contract with them, but I do have the original quote and the monthly invoices that they sent. The original quote also mentions insurance in case of total damage, which was actually one of the reasons I decided to go ahead with them.

I have talked with a couple of lawyers on the phone but they all said exactly opposite things, which I believe that this is because they probably have never dealt with a similar case, so I hope I can find someone who actually knows what the law says and can support accordingly.

I don't mind starting a court case, but I need to know if the commercial law is on my side and that they are fully liable.