You can get duty charges back from the CRA if you show them you shipped it back.
I had issues with ECS Tuning, when their website claimed they had replacement rear turbos in stock, but didn't, and told me it'd be a week+ to get them after I ordered the part.
At least they didn't attempt to charge me a restocking fee or anything, just annoying the website said they have them, when they didn't.
Also, with all the issues I've had with shipping, I've never once seen a retailer offer to pay return shipping. I think it's part of the mind game so you'll hold onto the part and they can keep whatever the profit is. I imagine the margins on bushings are pretty small, so they likely would have lost money had they paid for it to be shipped back.
Sending stuff via crappy post can be quite economical, if you're willing to wait 6-8 weeks to get your cash back.
Vishnu paid return shipping when my procede came to me defective. Then I lost the shipping label and then didn't have proper export documents when I tried a second time, so I just took it to a fedex location and paid for them to ship/deal with it, lol.
2016 e63 amg s wagon matte white
2012 bmw m5 JB4+BCM