Do i have the right to feel mad?

So i have an online friend, we mwt just for a few months, but he's really attached to me for some reason? And theres happen a few times before this that i kind of feel that she gets mad when i not respond (bc i'm bussy). But today he literally just blame me for always being bussy? And then i obviously ask why, and she said that she was sorry that she was just very sad bc he wants my attention , and that it was very inmature of him to do that. And idk, i just feel angry about that? Bc Ive explained her i don't feel good this days, and i'm bussy with work and school, and i think she thinks its an excuse, but it really isn't?????? Also i don't like when people put pressure on me to reply to their messages, i really dislike that. And she isn't even a close friend or an irl friend to try and do that to me?