I've seen people say they can't get the phone call on day 6. It won't work for me either. I re started many times and even restarted my laptop and I'm sure I did everything right.
I had this problem too for a while, then i found out you have to have triggered the trash cutscene on day 3 and talk to vincent, asking him all 3 questions, on day 4. If you can't find him on day 4 he is standing in the trash alley after the cutscene on day 4. hope this helps :)
I know this was ten months ago but I'm going to try this right now and see if it works since I'm also having trouble with it right now (i think I was doing the questions part wrong) thank you!