I would use Xbox Chat Support on their website. But they'll only unban you if it was a false ban. If not then you're out of luck.

sorry but you cant all ways to get account unbanned have been patched now.

If it was possible to do this i would of been have done it

You cant unban accounts they are locked forever, just like when a person dies in the end you move on

It's actually a really simple answer:

You can't unban an account.

There is no way to unban and Xbox Live account.
1. Support can't do anything they do not have access to anything that will ban/unban users
2. You can try posting on the xbox forums. You can appeal bans there but they are usually denied because they know you did something wrong.

I'm sure there is a way to do it, My friend was banned and he went to a friend and his account was unbanned everytime it was banned

It may have been patched cause this was long ago but still

Step 1. Get a job in Microsoft
Step 2. Get put into the head of unbanning and banning accounts on Xbox department.
Step 3. ????
Step 4. Profit