I hate to break it to you but realistically speaking, you won't get your RM300 back. Take it as a lesson and see the warning signs from his way of communication.

Why haven't you report to police? He will be getting away with it and continue scam others. Just look at his replies, trying to waste your energy and time, I don't think he even care about his reputation since he knows you can't get him. Maybank account and phone number also can close and change anytime. That kind of name can't find anything on Facebook. Take harsher action!

Anyway, sorry for your loss.