No problem. Not sure if that's what happened in your case, but it used to happen to me and I was frustrated until I found the solution. People replied to my comments right away, while I saw them sometimes hours after.

It was obvious they used some kind of a tool to be notified of new replies, I just didn't know what it was.

Then I found them, it may help you too, if you don't know them yet. You have two great options, one is Steemify from @blockbrothers, the other is @ginabot which works on Discord.