I finally got an answer to my question from prestashop CS, but it was totally unhelpful.
I do believe the staff who handled my issue wasn't versed enough at modules to understand the problem or didn't investigate it seriously.
I thought prestashop's official addons market was safer than 3rd party websites, but silly me, I just realized I already had the same problem on addons.prestashop.com a few years ago, and this is 2nd time.
Anyway, though I was a bit late, I learned a lesson.
The crappy 99,99€ module I purchased through addons market is sold only for 50€ on the scammer's website, which means I could have ended up losing half instead of 99.99 if I had gone there.
Now I can clearly say there is no buyer protection here, and no need to pay more to Prestashop Addons for nothing.
From now on bypassing Prestashop Addons will always be my 1st option.