Don't buy from hrkgame.com, once you paid, they will lock your account and order until you uploaded any sort of ID. You won't get your money back, nor the game(s) you ordered.
Never had an issue with HRKGame. I always purchase my CSGO keys there and some other games. 20+ orders no issues. I always pay in BTC... maybe thats why. Its possible you are paying in PayPal and they think your payment was fraudulent and want to verify you