IT BUGGED WHEN I BOUGHT SOMETHING IN THE STORE I LOST RP

I had 3409 rp beacuase i just bought a 25 dollar pre payed card and had some left over anyway i bought

Sejuani and poro rider sejuani and for some reason all i have is 579 rp left

where can i talk to someone about this problem and if u do the math it would mean that i bought poro rider twice

also in my purchase history it doesn't say i bought anything else recent but sejuani and poro rider