ANSWER:

This is pure theft and you have committed a major sin that was more than their own original sin. 

QUESTION: I found the glasses of a Muslim who uses them for haram and took the earphones of someone who left prayer (he may pray now) who listens to music.I kept them because i didn’t know what to do now they bought new things.should i give things back and do i need to pay the things they bought new.the one with the glasses prevented me from learning about this.can i just take things a muslim uses for haram