Warning for double purchase on account or credit/debit card

I recently attempted to purchase $20 worth of RP and I was led to believe it did not go through, as I attempted to buy it again it went through along with the first attempt so I ended up spending an extra $20. It sucks yeah but I can deal with it. Although I feel it is necessary if Riot Games implemented a system into the game where there are warnings that a card was recently used to buy Riot Points or the account has recently bought riot points (i.e. in the last two hours)

Please support this idea, it would avoid problems like what happened to me last night. Thank you!