ribara1 ""self vouching"" ban and TWC

I've just been banned and TWC'd for the following reason: "self vouching" Lyuboslav/ribara1 - self vouching
We actually are two different people, he is my brother and I really traded with him OSRS gold, so he vouched me.I didn't know this was not allowed and I don't know what's wrong with that to get a 2 week ban and TWC status. I have never scammed anyone, my next vouches prove that. I didn't know this was not allowed, he is a student learning in other city (Sofia) have his own PC, but at the moment he is here and we live in the same house right now. As the forum say "Please note that just because two users have posted from the same IP does not necessarily mean both accounts are owned by one person." I don't own the two accounts.
How to prove that and get this problem resolved?

This is not fair, i did nothing wrong, he is a real person who is satisfied with my service. Whats the difference if he is my relative or someone i did not know. His registration is 5 year old, he did other sales with other gold shops
i didn't expect it just enter the site and I'm banned