Intentional Tk's are against server policy. If you see this happening you are welcome to record and post here so that it can be dealt with. We cannot be online 24/7 to look for offenders. When we are online, we are usually enjoying the game!
Unfortunately, you are not banned by us directly. You will have to appeal with both BA and BF4DB to lift the bans.
To be fair, you did throw quite a bad grenade. You threw it after your other teammate ran through the hallway, when you could've attempted to cancel the throw or throw it down the other hallway. However, it is not acceptable for him to intentionally TK his teammates, even over a bad grenade. Try...
You are banned by BA and BF4DB. You would have to appeal to both of them. If you're simply wonder why, here are the links to your bans.