Under normal circumstances, it's usually best not to break up with someone through text. But your case was a bit different. He was avoiding you and you weren't able to deliver him the proper break up but you felt like it was time for you to cut ties. I would say that in your case it's quite understandable and you shouldn't listen to those people who tell you otherwise, especially if they don't know the whole story yet. But if this were different and it was you who had been avoiding him the whole time and then you broke up with him through text, then that's not cool (kinda like what my ex did in my last relationship during the second time we broke up) because you, the one who wanted to initiate the break up, was doing an injustice to the other person rather than that person just doing an injustice to themselves. So yeah, just don't worry too much about it this time and resolve to breaking up via text only when necessary in the future like you did in this situation.