i cant message on xbox

Its best not to mess with the report system as all reports are reviewed by the enforcement team and even if you only reported a player for a joke or you know the player the report cannot be undone and will still count against them if they broke the code
of conduct.

This sounds like an communication ban but to make sure check here as it will tell you if you have a communication ban. Have a great rest of day or night.

You should log into the enforcement team website for information where you can also submit a case review if the suspension is eligible.
http://enforcement.xbox.com/home

Verify your account here to see what is going on...

https://enforcement.xbox.com/

For future reference, please don't abuse the report a player system to troll/prank somebody. As others have stated, it sounds like either you or your cousin have been given a communication ban.