We have been getting hit hard with double brokering but, with the help of loading and receiving warehouses, we have been able to stop it. Thought we had all strategic processes in place until last week. Before Carrier A was loaded, we confirmed MC/DOT on the truck matched up. Sometime after pickup, our cargo was offloaded and loaded on to Carrier B who in turn delivered our freight. Although Carrier A's factoring company sent us an invoice, they advised we legally do not have to pay them as dispatch never submitted the load to them. Carrier A expressed frustration that I reached out to their factoring company. To find out, he had no intention of submitting this load to them and only did so after the Factoring Co called to find out what was going on. Carrier A & Carrier B have separate DOT/MC #'s, addresses, etc. Although separate, Carrier A is trying to justify his actions in passing on our load saying both carriers are owned by the same person. I did obtain the carrier packet from Carrier B and sure enough the W9 is signed by the same person who signed Carrier B's W9. If owner in fact owns both entities, this still does not provide a loophole to double broker and do not want to get caught in games when it comes to payment as both physically had a part in the load. Carrier B has yet to reach out requesting payment. Has anyone run into this type of scenario and if so, how did you handle resolution?