I think his problem is the payout of the post reaching over $200. I don't know if he listened to your music. I think he feels his downvote is justified.

Theycallmedan has done a lot of good for Steem for most of this year. He contributes prizes, he actively promotes Steem on social media and he provides motivational material. Downvoting out of spite would be out of character for him.

I also want to give you credit for your music and your original work. Thank you for adding value and attracting people to this platform.

Even if you think you have been unfairly treated, throwing a rant and insulting someone does not reflect well on you. You are a professional and you are better than your vulgar display in your response.