When should I call back?

So I had an interview last Friday for a Network Admin Intern position. The IT Director told me at the end that I was at the top of his list. He's interviewed 8 people already and no one has fit with what he's looking for except me. When he walked me out he said "we'll definitely be in touch" and told me I'd hear from him next week.

When I got home to send my thank you emails the HR Manager told me I'd hear from them Monday or Tuesday to setup a 2nd interview. Then the IT Director emailed me back Monday and said "It was great speaking with you as well. We will be in touch this week, I may have you meet some of the team members depending on availability"

So...I forgot to switch my payment on my phone and my phone service was shut off until 2 pm Tuesday. I'm now worried that they might have called me. However, I would think they would have tried again or emailed me. I don't want to seem like a pest so when is the appropriate time to email the IT Director back? Should I do it now or wait until the end of Thursday? (so he'd see it Friday morning)