1. The textbook implementation involves 3 parts: tax, rebate and tariff. Canada only did the first 2. They were in talks with Germany/EU to create a carbon tariff zone, but that never happens. Without the tariff the carbon tax is massively unfair to local producers.
2. The rebates were almost invisible. If they would have been cheques in the mail it would have had much more impact psychologically.
But I agree, the main problem was denialism and its use as a political cudgel. It should be hard to argue that carbon tax is stealing money when all of it is given back, but they successfully did that.
Second, and probably more important: the rebates showed up in your bank account with a description that didn't make the source obvious enough for laypeople. Had people seen monthly "CARBON DIVIDEND" credits in their bank accounts, they would have noticed.