Player Disrespect

[King Kickass]

Nevy said:

"The /blockpm <username/ID> feature was made to block people who were insulting/annoying you in Private Messaging."

You can of course post a ban request on them but that would lead to even more resentment between you and the other person.
i recommend you BE the better man ( or woman  i don't know what gender you are) by blocking them. 
this is only my opinion of what i would have done in your shoes though and you are 100% entitled to make your own decision.

hope i helped.