So I got a survey from Anker and when I clicked the link and answered what I needed to I decided to go back using the link and it stated I already answered it.

My default browsing app is Firefox focus on ios and wiped all data when done. Tried it in brave private mode and ddg all on ios and it gave me the same results. Finally I opened the link on Mullvad browser on my pc and still the same result.

I understand why they have trackers that knows if you completed or not and I’m not faulting them for this, just trying to tinker and figure out how it works. My guess is that the tracker is associated with the alias email and the link can be disabled or show a certain message once I reach a certain point. If anyone knows how to this works please inform me as I would like to learn how this works and would appreciate this lesson.