The loss is inside somebody else's policy
Goods damaged in transit where no marine cover was ever bought. A contractor's work that damages the building it is being done in. A fire that starts next door and comes through the wall. A vehicle that takes out the boundary and the gate. In each of those the business has no policy of its own that responds, and in each of them the party that caused it is answerable for it and carries cover against exactly that liability.
You are told the loss is uninsured. That is true of your own policies and says nothing at all about anybody else's.
We establish who was answerable under the document that governed the work, whether that is the consignment note, the contract or the work order, and put it to them in writing inside the time that document allows, which is usually shorter than anything on your own policy. Then we deal with their insurer, rather than leaving you to argue with a transporter who has stopped taking the call.