Prohibited Text in Clan Tag

Hello. My name is Heather and I play Call of Duty: Black Ops. I am a member of a clan called TMS. Within the clan, we have different squads. I am a member of Bravo squad. I am having a problem with prohibited text. For our clan tags, we put TMS and then a squad letter; mine would be TMSb. However, anyone that has a gamertag starting with the letter 'H' cannot put TMSb due to prohibited text. This is what I mean: [TMSb]Heatherly13ox That is what it would look like... But it's prohibited ONLY for people whose gamertag starts with 'H'. I was wondering why this is prohibited and if there is any way to fix it. Please do not tell me to contact Microsoft Support or the developer of the game as I have done both and they have lead me in circles. Microsoft Support told me they don't deal with it and to talk to the developer of the game. I contacted Activision Support and they told me to look up acronymns on the Internet and to recontact Microsoft because they're the ones the deal with it. I re-contacted Microsoft and they told me to post it on the forums. Microsoft deals with gamertags. Actvision deals with clan tags. I understand this. But whoever chooses what's prohibited and what's not is the person I need to talk to. I have obtained terrible customer support from both companies so far and I am highly disappointed.