What I have done on rare occasions (I sure hope this isn’t against Envato policy!) is this:
One of my first actions only work in English versions of Photoshop. This IS stated on the product page, but ever so rarely some doof won’t read the description and just buy it anyway, and then have a problem. Some chuck it up and realize they should read a bit more carefully, others feel quite bad about it. Now, if a customer is just raging, I feel no obligation to help them. But if they contact me in a sincere manner asking for help, and actually feel bad about their mistake, what I sometimes do is send them a free copy of my video tutorial, covering the same effect as my Photoshop Action, hence at least still giving them the chance to achieve the effect they wanted, though perhaps not quite as fast.
Happy customers are worth a lot Though the raging and impolite ones can just kiss my behind.