[let me buy platnum]

When buying a steam card from my local store I came back to put it in my steam account ready to buy more plat with it. when i tried to pay with my steam wallet an error appears each time i try. I fallowed the steps that are there to help and re-logged into my Steam account, Warframe account, and the web sights for each and tried to buy plat again only to find the same web page error from the first time i tried to buy plat. I started to get a bit frustrated and decided to go through steam to buy the starter pack. usually when i buy platnum there's no problem and it arrives in my account as soon as i log into the game after i buy it, so i decided to allow my computer to rest and buy a couple more steam cards the next day. once i came home and put the cards in i tried to buy more platnum only to run into the same issue. thinking it was just my computer i tried to log into my account through another computer only to run into the same issue. 

can someone please help me?