No roof survival load

I've been trying to play rooftop survival for about two or three days now, and it won't let me in.

I was playing that level before, I was almost halfway through but I quit the game to take care of something 

When I tried to log back in, that's what happened; it wouldn't let me in at all. I can play the other levels like pool survival or fog, the problem is only with the roof. I've already tried restarting my device and turning it off over and over again, and it never works no matter how many times I try.