You are confusing obligations, and emotions are getting in the way.
1) You have no obligation to the final carrier. Your deal was not with him/her.
2) The factoring company has no obligation to the final carrier. Their deal was not with him/her.
3) The final carrier struck an accord with the carrier you selected to move the freight.
a) The freight was moved (presumably) without issue.
b) You paid the carrier invoice for moving the freight presumably with proof the job was indeed done.
c) Your job is done here. There is nothing more for you to do.
Without question this sucks for the final carrier, but you didn't make the deal with the devil. S/he did. S/he moved a load without recourse. Such is the unregulated Canadian brokerage world ... it's the wild f'ing west out there. Perhaps a more appropriate colloquialism is "It's literally highway robbery.". However, for better or for worse, double brokerage is not illegal.
On the other hand, not paying for freight moved, regardless if it is double or quadrillion brokered, is illegal, especially if it is premeditated. That is called fraud, and lands a convicted perpetrator in prison.
HOWEVER, IT IS HIGHLY UNLIKELY ANY POLICE FORCE IN CANADA WILL INVESTIGATE SUCH CRIMES.
(LEO's are far too busy making sure every Tim Hortons is safe from the common riff-raff)
Just keep in mind, in Canada, under the current judicial system, a person can get away with every crime imaginable, the first time.
The one exception, unless you are ultra-rich, is tax evasion. The government will spend untold millions to collect a couple hundred thousand from middle class and poverty stricken Canadians.