Treating a cat in pain

My senior cat tore her ACL (cruciate ligament) and had a bad limp. The vet ordered drugs and keeping her in a cage for a month to get better. (They don't do surgery on small pets so this is not a cure.)  Unfortunately, she reacted to the antiinflammatory/pain drug Metacam. The alternative was opiods for the pain. The vet would not recommend CBD oil (aka didn't know anything about it).

I bought Fortify250 for small cats and dogs online. On March 25 I started her on the recommended half-dropper (5 mg) A few days later she went down the stairs for the first time in a month. Coming back up at an angle with 3 good legs was not elegant, but she made it. Then jumped on the bed!

I had read online that cats don't digest plant oils very well - and this product has MCT coconut, hemp seed and pumpkin seed oils, so I searched for pure CBD isolate powder.  I had trouble finding a Canadian source so ordered from Colorado (10g $120usd). Too good to be true?  Yes - the package was stopped at the Ontario border. UPS tracking stated "the product that is to be imported is prohibited."  I found a CBC news story "Cannabidiol oil won't get you buzzed but it could get you busted". CBD apparently is a controlled substance.  It isn't made from cannabis plants (but can be) and it has no THC at all (so no "high"), but I can't legally import it. Even the company I bought if from didn't know. How crazy is that?