Gift card redeemed but no coins received

I WANT THE PRESTIGE SKIN FROM THE URBAN ASSAULT EVENT, AND PURCHASED 100 DOLLARS FROM STEAM BUT WHEN I TRY TO PURCHASE THE APEX COINS IT SIMPLY DOES NOT WORK, IT OPENS THE STEAM POP-UP BUT NEVER GOT THE COINS AND MY STEAM BALANCE STILL THE SAME.

FIRST I TRY THE 100 DOLLARS DEAL BUT NEVER WORK SO I TRIED "JUST IN CASE" THE 60 DOLLARS DEAL AND IT WORKED BUT CAN'T BUY ANYMORE, AFTER TRYING SO MANY TIMES THE STEAM POP-UP STOPS WORKING AND IT DOES NOT SHOW ANYMORE, MY STEAM BALANCE ITS 40.62 DOLLARS, I NEED HELP BECAUSE I WANT THE SKIN SO BAD, PLEASE.