I would suggest reading this publication:
https://www.cbsa-asfc.gc.ca/publications/dm-md/d8/d8-2-10-eng.html
" Goods Returning to Canada Having Been Repaired Outside of Canada"
Near the end of the document, there's 'Addition Information' that has a phone number you could call if required.
https://www.cbsa-asfc.gc.ca/publications/dm-md/d8/d8-2-10-eng.html
" Goods Returning to Canada Having Been Repaired Outside of Canada"
Near the end of the document, there's 'Addition Information' that has a phone number you could call if required.