Can contractor do my roof without notifying me?

[Vadim Du]

I paid a contractor 50% deposit to replace the roof in my rental. They were supposed to notify me later when they going to do the job. 

Now I come to find out that they already did the job last week, without notifying me.

Asked them for pictures that show that they tore out old roof and raised the A/C units before placing the new roof. They said they don't have it.

Anything can be done about this?