Anivia Bug

i recently bought and tried to use her in a teambuiler lobby (solo) and she did not appear in my roster i assumed it just did not go through so i logged out and back in and she was there, i picked her and everything was going fine until i pressed the find game button the button turned grey and displayed an ERROR_INVALID_CHAMPION pop up box. i logged out and back in to see that she had dissapeared from my roster all together. now every time i want to play it is a guessing game on if i will be able to use her. These same issues seem to reoccur more often than me being able to actually pick her and enter a game lobby to play.