Totally your fault.
But it happens don’t let it get to you just learn from it.
Never rely on the camera either those things often cause more mistakes then they prevent.
LS222:
All these drivers saying they can’t believe you reversing into a stationary car. It’s one of my pet hates when cars drive round me when I reverse. All she had to do was wait 10 seconds.Sent from my SM-G950F using Tapatalk
My pet hate is friggin pedestrians doing it!
I the same vein …I once knocked one o my gaffers flat on his arse(he was a good old boy,worked his way up from sweeping the floor)…. I had complained for ages about an access I had to use to get in to load a long wheelbase 6wheeler …wae a fair overhang. Anyway he came out and saw my problem then went away (I thought ) but he stopped to clean my rear camera /lights out o my sight,i missed him stepping behind the wagon. and yup I shunted/rolled back and the camera clicked on when I reversed only to see Ian being smacked in the back 
… he wasn’t injured just pride (both o us). ■■■■ runs for a while but lesson was learned.