Marshall Motors- disgusted client

We bought a Dakar 650 motorbike from Marshall Motors. After purchasing a road bike we decided to sell the Dakar 650 through Marshall Motors. In good faith the bike was taken there in February by my husband and it was sold on 7 March. We were not informed. In April my husband went to the shop to find out if there had been any interest in the bike. Only to find the shop closed down and all the stock gone. We were not informed by the owners of any of this. If we did not go to the shop we would still not have been told. The bike is now transferred to a new owner. My question is: How can businesses be allowed to get away with this kind of action? We trusted them as a well known business only to be ****** in this way. I do not understand how a business may sell something that does not belong to them and keep the money. In my opinion it is theft and certainly not something that businesses should so easily get away with.