What? Are you kidding me? I know you are not. But, C'mon dude. I cannot think that you did it. How you can send 26000 euros to a stranger? First of all, You never know who is behind it. You don't them personally. You never met them. How can you send that much amount? Sorry for your loss but you should learn a lesson from this. I always follow some rules before doing any transaction with an unknown person. Either I don't pay first. If I pay, In my case, I would send him a maximum of 100 euro and ask him to complete the deal. If the deal becomes successful, I would do it again with a maximum of 200 euros. In That way, I would increase the amount. You should never do all in. That was the biggest mistake you made.
Thats not the case always. OP may have done many smaller transfers and even work with him for a long time and trade more than 26k in total, but when the amount became sufficent enough then other party decided to scam. I am not saying this happened here, but it may have been like this.