Okay Riot please help me out here, I do not know if this is a bug or not please read.

I had around 3000rp left, I bought yas champ alone and now seem to have around 1120rp... Why did it take all my rp, I did the math and was going to buy him and the project skin then get fioara when it was on sale.. Please let me know if you can get me my rp back, I am sure you can look at the logs or something yas does not take all that rp to buy normal.