Okay, here I'm gonna explain how to answer to a comment
You go to the top of your screen where you see the little envelope and a white number beside it. The number is how many messages you have. You scroll over it, and you'll see a number and then "deviations" and or a number and then "feedback messages". If you click "deviations", you'll see drawings or stories. If you click them, you'll go to their page. You can then scroll down and click the little white box under the deviation and add a comment, or click the little red "X" and delete it. For the feedback messages, you can click "original" and see what you have posted that the person replied to. Then you can click "reply" and reply.
Darya said that you werent replying because you didnt know how to work the site XD So I figured this might help...