The usual way that a mech plate breaks like that is when the chain has derailed from either the pulley or the chainring and the chain has been pedalled through. Standard OEM carbon mech plates are very stiff but quite brittle as they are manufactured from UD carbon fibre usually. In my experience, although obviously bias, our plates are a lot more durable. They will still break if you hit them hard enough though!
This is where it gets more complicated. Looking at your derailleur, that's not a standard Red plate, the profile is different. I guess they altered it on the black edition. You'll need to check the distance between the pulley centres, but also check the pulley bolts to see if they're M4 or M5. M5 is the 'standard' that Shimano, Campag and most o the current Sram range uses. However, Sram do use M4 bolts on some of their derailleurs and our standard plates won't fit those. If your nt sure send me a pm or email me at work (email@example.com
) and we can work it out. If the standard red plate that we do will fit, then you'll be able to obtain one through our hosts.