I've been scammed for 100$ on DP. For some of you this isn't probably the worst thing that can happen, but it sucks for me

The problem is that I can't ask for a refund, since there was a problem already and I refunded the money. That problem was solved so I closed the dispute and now ofcourse I see that the bought template (for 100$) can be bought on Themeforest for 15$. The seller told it's unique etc but it just isn't.

What can I do now? Someone? Thanks