... Does it still comes under only Canadian law?
No, it does not fall under Canadian law ... it is subject to the U.S. Carmack Amendment. Learn both the Canadian and U.S. rules and figure out which serves you better, then try and mitigate the loss under those rules. It will probably work if the claimant doesn't know the law.
Things to look out for overall ...
1)
Do not ever, ever, ever, ever, ever (ad infinitum), tell the claimant how to process a claim. It is their responsibility to know. Ignorance of the law is no excuse.
(My response when I get a call telling me I'm being claimed is simply "Thank you for the heads up. Please follow the correct procedures.
END OF CONVERSATION.)
2) The claimant must file an "Intent to claim" with you in writing, and there is a time limit on that ... 9 months I believe.
3) You are not obligated to settle any claim until you have been paid in full for your transportation services. Send only one correct and complete invoice and do not pester their A/P to pay it until you are well past the 9 month time limit.
4) Do not allow the claimant to deduct from your transportation invoice. That is a separate transaction. Contra-charging an account is illegal. If they do, you can either;
a) Sue them for the difference, and you will win, or
b) Have them criminally charged ... they stole your money.
5) If you manage to get the claimant to mitigate under Canadian law, you are only obligated to pay manufactured cost. Make sure you have the costing documents before you settle.
6) Under Carmack you have to pay invoice cost, but make sure the receiver mitigated the loss on your behalf, and deducted that from the claim, or you don't have to pay anything. (Receiver is important to this part of the transaction).
There are a myriad of tactics to use to get out of a claim. Bedbug haulers and railroads know every one of them. It would pay you in spades to know everything there is to know about the claims process as well. Typically the process can be made so onerous the claimant will usually give up, unless of course the claim is for a huge amount.
Luckily for you, you have 11 cases of over-shipped. You do still have those cases in storage, and you are charging for that storage, and you did issue an invoice for returning those goods, correct ???