need serious help

If you report it and he make always new account to find you, I suggest you to block it again and change your gamertag istantly, so he cannot find you anymore, but be sure that you don't have friend in common...

All you can do is block and report as said above . And hope Microsoft will catch the gamer. I hate this sort of thing happening an it is totally wrong.

What ever you do dont rise to the bait of answer back or you could get a enforcement against you 🤔🤯👍

Just ignore report any bad messages block him change your gamertag name maybe dont rise to the bait my friend

have you checked you internet to see if you are being throttled? check your speed for free at www.speakeasy.net click the speed checker tool it will pitch you faster internet afterwards but you can ignore it anything 1 or under you may be throttled. that
would be a call your ISP problem

"If that does not work try resetting your router." (sorry)

Well, it's a good idea but It didn't work It's the strangest thing in the world, also, that joke was expected, I mean, I was going to make it myself if no one else did.