Canada seller, How to solve GTIN for global product

Hi, I am a canada amazon seller based in Canada. I have been selling on amazon for quit a while, I usuallly use GTIN/UPC from random website to list generic items. Recently, I got authorization letter for selling a global product, the item models cannot be found on amazon, but while listing the product amazon were requesting for so many stuffs including GS1 certificate which i have never gotten before. The product company said they dont have any of such. I submitted the new UPC but amazon wants GS1 Certificate. When I checked GS1 website, there price is too high with annual renewal.

As anyone here be in this situation?

will getting GS1 GTIN solves this (I am sceptical because of the price, I will if chances of success is high),?

Any better way to solve this?