It's because of the nickname database update that allows players to 'book up' an already existing nickname. If the player whose nickname has been booked up won't appear in the game for a certain period of time, his nickname is passed to the one who reserved it. You can find more information here: http://en.tankiforum.com/index.php?showtopic=315003
Yes, Master of Taiga is available from Lieutenant General to Marshal in the garage.
Go to your garage, click the turret for which you want to buy an alteration.
Once you click it, these boxes will show up (green represents the alterations that are currently available for purchase.)
Click once again on the green boxes and you will open their description (e.g. Firebird's high pressure pump)
If you like one of the alterations, click the buy button. Please note that if you want to buy an M1 Firebird alteration you must have M1 Firebird, if you want M2 alteration of Freeze you must have M2 alteration, etc.
This might be caused by Tanki's anti cheat engine. It sometimes affects normal users who cross a certain elevation level and the engine mistakenly interprets them as fly hackers. This phenomenon often manifests/manifested when you try to climb on top of Mammoths. It's a well-known problem of anti cheat engine.
Since it's no longer listed on Wiki, I presume it was permanently removed. It's possible M2/M3 (like Bulldozer) kits won't available before Brigadier since the M3s unlocking rank have been moved to Marshal.
Try to clear your flash cache as well.
I tried to google some solution and found this. Click the link. It may solve your problem.
Are you sure you bought every single M0. You might have skipped one of them by directly buying M1, I guess it doesn't count in that case. Also did you purchase the new Striker turret?
If he will send you a friend request next time, do not decline it, but rather keep it in the incoming requests. That way he won't be able to spam you with another one. Also completely ignore him. These types continue to troll people if they see it bothers them. If he won't see any reaction from your side he will eventually stop.
Did you provide anyone your password (maybe a friend or some unauthorized page)? If yes, there might be a chance your account has been stolen.
In that case check this page: What to do if my account has been stolen
But before that, try to login again and write your nickname and password slowly and carefully.
Customer support service by UserEcho