[CLIENT] Can't buy champions in the store

In the store I can't buy any champions with ip. I have currently 1387 ip and I would like to buy Dr. Mundo with this ip. But I can't although I have enough ip to buy this champion. I tried to buy other champions with the same cost but causes the same problem.

1. I open the store
2. I click the category 'CHAMPIONS'
3. I click the filter 'Price Ip î '
4. I click on the icon of Dr. Mundo
5. The prices appear in rp and ip
6. The price of 1350 ip doesn't light up
7. I can't buy this champion or any champion of the same price