This is exactly why I get easily agitated when I read some of the posts on this site, and evidently in this thread. When you see something you don't know how to defend against, you need to sit back and seriously think about your options. When you break down any situation into it's possible "what if" outcomes, you begin to realise you have more plausible options than you initially thought. Yes plus frames can be hard to deal with, but you have a multitude of options with how to deal with it, especially if it's just +6 as opposed to something like LK's f213 rc plus frames. And if not, you eat some damage, gain some meter and have an opportunity to turn things around (yes, I AM suggesting that you can turn things around when you're knocked down. The get up game can be as bad for the attacker than the defender). Then on top of that, there's the possibility of simply being patient and blocking. But he can get a free 50/50 if you stand there and block? Yeah, sure that's a threat but pay attention and you can decide if the attacker is favouring one option than the other. Maybe he LITERALLY ALWAYS goes for the 50/50 after being +6. In that case, you're more than likely going to have meter at least one time when you defend against this, so spend a bar and armour through that shit.
Seriously dudes, see what you get hit by, replicate it in training mode and see what you can do. It just takes a little effort, but it's incredibly empowering when you completely understand what's happening.