League is Scamming me out of ip

When ever i'm really close to buying a champion like today i was saving ip for miss fortune and had 3122 ip then played a blood moon game mode to get enough ip to buy her after the game i had 3177 ip which is enough for her since she only costs 3250 but after the game my ip randomly dropped and i now have 3043 like wtf??? This isn't the first time its happens to me either last time i had riven i would randomly loose ip from playing and i may just be a bug from blood moon because last time i was grinding ip it was on the blood moon rotating game mode but i'm getting annoyed that i cant buy the champions that i put so much time grinding for. please somebody fux this bog or give me back my missing ip this isnt fair.