How often riot go to best buy put card in canada cuz there is no more for about 1 month

I believe that's specific to the store in question; if they don't order more, they won't get more.

Ask them if they're planning on getting more, or if they know any nearby stores that have them in stock. (They'll typically check other stores of the same franchise, i.e. other Best Buys, to see if they have any in stock, but some employees will also tell you if they know a nearby shop that may have them.)

Riot doesn't put them in stock. The store orders them from Riot. Ask the store when they will order more.

There's a ton of RP cards in my area. Pretty much every EB Games, Toys r us, Best buy and future shop i went to in the past 3 weeks had a stack of rp cards.