The problem is that the term “After Effects” does not really indicate it is a name of a software, as it could simply be the name of these kind of “Effects” we are selling - After Effects - like Visual Effects.
However, when there are things like Version numbers mentioned one could get suspicious. I still understand how this can happen to someone without experience in this area, though.
There are some solutions now: Best is to use the trial version of After Effects and try out if you can edit the template yourself with that.
You can also hire someone to edit it for you, this does mean to pay again, though.
You can contact the author and ask for a refund.
You can also contact envato support and explain the situation, but in general the rule is: if you downloaded it already, there is no refund.
To contact support, you can go to this page:
https://help.market.envato.com/hc/en-us/requests/new