Blackkk scammed me $10.00 USD false promise

Blackkk said he could obtain a fire cape for me at lvl 52 range
He said he would do it for $20.
He did nothing on my account except for sell all my prayer pots and bought 2mil worth of junk, i pmed him he said something turned up and that he could not do it. He said he would give me a refund and i still yet have to receive the money from him.
We agreed to go 50/50 i paid him 10.00 USD

 

Provide proof of trade (convo screenshots).