Thanks for wanting to report a bad behavior in Discord !
First, please read https://dis.gd/report.
Then, send a request to Discord for "DCMA" at https://dis.gd/request
In general, you can directly contact Discord about something you're not sure and they'll redirect you.
He's just using the same profile picture as you, no biggie
Are you insane ? Its just the same picture.
His name isn't even close lol