Is targeting someone who's 8 levels below you wrong?

[Teeaaa]

(I don't know if I posted this in the right place, so if I didn't then sorry)

I've been having problems with this level 21 guy, who's been targeting me

Targeting isn't the strong word I need for this... What I mean as targeting is killing me every time I step foot off the ledge, and yes I jumped off to try to battle my friend 10-20 times and it never stopped until I decided to quit then and there.. and not to mention when I kindly asked This guy to stop killing me, this response came up

(Tell): ------ tells you, 'Don't do request for peons.

I don't know if killing people instantly is allowed or not, but would also like some suggestions to respond to this, where I can fairly battle my friend and have fun..

I am not saying that PVP is bad, I love PVP, but it would be nicer if I can actually pvp fairly