Not being able to buy Champs with IP

So Right now i have around about 3900 IP sitting in my balance and i thought its a good time to buy a new champ. So i went to the shop to buy (3150 IP) how ever when i scroll down to the 3150 champs all that i have not unlocked appear with a red text over the IP. When i click on buy champ the game believes that i have 3108 IP although i can clearly see on the top of the screen that this is not the case. This happened yesterday, i relogged several times and even restarted my comp(for some reason) and yet this problem still persists. I am unsure of weather this is a problem associated with my account or simply a problem with the lol files on my comp, but it would be great if a solution to this problem could be found, thanks for reading :D