I thought I had the same problem but I randomly went to the hotel in Las Vegas and Kim was there with a speech bubble. I hadn't finished my task by talking to her and that was 3 days ago. Hope this was the problem instead of a glitch.
I'm on level 20 experiencing the same thing. Maria no longer calls me and I have done 15+jobs. Games getting a bit monotonous hopefully an update comes out soon cos I've been reading about a lot of different jobs people have been going on and I'm in limbo