Tradable player to untradable after maintenance.

Hey im such a big fans with this FC mobile game i already spend alot of money for upgrade my team and collecting 8 billion FC point but.. its all gone when this bug happend.. i have same problem with tradable player its suddently change to untradable player after maintenance its makes me lose alot of FC coint on it around 7 billion fc point, it was i buy ruud gullid with 4 billion and rodry 3 billion something when its still new card, please give me some adviced at least you can resolve this problem.. may be you can considering give me back my 7 billion FC point. Please let me know if you notice my complain thanks. And some advice from me maybe you can give history record for us when buy and sell player so you can see our history when spending FC point, then you can check if this player tell the true or not. This will be great feature. As player who really enjoy this game i really hope you really care with player who spend money for this game.