I've done KYC to hitbtc without encountering this issue but I don't really like exchange especially there volume is so low and they also have a flat rate withdrawal fee. Even though they have a lot of bad reputation, There customer support keeps in touch whenever you ask an update.

In case OP, Maybe there's a difference on the details you provide on your Hitbtc account and to your passport because they will not tell you that you modify something in your picture if your passport is really authentic or match with the details you provide to them. How much money we are talking about here?