Leveling Off Friends Lists to Include ONLY Mutual Friends!

make sure that you do not share a mutual friend on xboxlive.

if you block and avoid someone and you both share mutual xbl friends that "blocked" person can still contact you until you remove said mutual friend or have said mutual friend removed the "blocked" person from their friends list.

besides blocking this person and submitting a player complaint you have done everything correct.

Pay $10 to change your son's gamertag and then don't tell anyone (especially the mutual friend who might be allowing the harassment to happen)! Alternatively, you could ask the mutual friend to remove the harassing individuals from his/her friends list too
or simply remove the mutual friend as JPep has already suggested.

Sorry but when a gamertag is banned it is removed from the system, including xbox.com. However, if you have mutual friends that were on your list perhaps you can find most of them through that way.

Is there anyone on your friends list that could be a mutual friend or maybe a google search of what you think his GT maybe?????

^^ If you have a mutual friend with this person, try and view his/her friends list... you should find the blocked person's gamertag on there.