Looking at a premium vehicle efficiency in game is a big factor for me to either buy it or not. Now changing the BR of the vehicle means altering its performance and i would not have bough it. I want compensation.
Not sure this is the place to redress your issue. I would suggest going through the store.
Rather than give you compensation they close the game.
The game developer reserves the right to make adjustments or changes to any vehicles in the game (not just premium vehicles) for balancing considerations. This is a typical occurrence in other games as well.