I don't know, my dude. Honestly? It sounds like you got owned pretty legitimately with the bolded. I don't know what to make of that, but to say it sounds like a clutch play by Genji or dumb luck. Whichever you prefer. Maybe he's just not a good match up for you?
Not trying to be a dick. Honestly, I don't even think of myself as being very good, I'm just not seeing the issue here. Seems like you need to learn how to address this character before Blizz makes s change that'll potentially, ostensibly make part of his kit useless.
I can list several different situations with different chars and some random genji deflect when I'm not even aiming for him screws things up. It doesn't even have to hit me, but it goes to an ally. In the situation I mentioned my shots just went elsewhere and not to me. But how the hell am I to know genji's deflect is protecting someone else.
Genji can be behind a doorway, looking at someone else, use deflect. And depending on the angle, the shooter will never even know genji was there but the deflect is bouncing the shots. Shooter is safe but if he was aiming at a target the he'd be wondering whats going on.
Genji can be inadvertently protect a teammate with deflect and no one would know because the hitbox is so huge with no visual cue to it's size. Shooter can be up high aiming at the ally beside genji but can't even hit the target. But ends up shooting a teammate that genji is aiming for because he has deflect up with no visual cue to it's size.
I literally have no issues dealing with genji. I do have an issue with deflect just blatantly lying about it's position. Sure it's supposed to cue to enemies not to shoot him. And thats entirely fine. But even if you don't intend to shoot him you can still end up shooting the deflect just due to not knowing how big it is.
I don't care if they don't change the hitbox size. Hell Blizzard can buff Genji's deflect for all I care. Make it the size of the map and thats fine with me. I won't shoot during that time. Just make the damn hitbox match the visual cue.