IP number malfunctionning

I have a problem with my IP, it shows I have 3498 IP but if I want to buy a champion that costs 3150 it shows that the remaining IP after the purchase will be 57 IP, if you do the math it should be higher than this number. I don't know if it's a porblem with my first win of the day, it probably is, but I do not have the rigt of IP I have, so does one of my friends.