need help with scammer, asking more money after he received already

Hi there,

earlier today I purchased several
http://steamcommunity.com/market/listings/730/ESL One Katowice 2015 Cobblestone Souvenir Package

from a people via paypal and skrill.
Sometimes I went first, sometimes they went, but transaction was made fair and square.

After 6h, I am getting whispers from one of the traders I purchased case, them saying
"Hi I didn't got cash, can you send again or I report for scam!"

I have paypal/skrill evidence of them accepting the cash, everything was fair from my side, I didn't withdraw money, sent it as gift and left it to them. One of them didn't even accept the money, since apparently he doesn't even know how to, and quite honestly I even explained it to him once, but he failed.

What am I supposed to do if I get reported here on steam rep, since with that evidence and paypal log of them, can show one thing, and I can sure show my side of story.

I am sick and done of steam scammers everywhere, especially from people with lvl 1-4 profiles.

Would like some advice.
Kind regards,
K-man

Thank you very much, will try to keep an eye for steam reputation.
Kind regards,
K