Peter: Hello Maria, it's Peter. How are you?
Natke: I'm fine. How are you?
Peter: I tried to call you on your mobile phone but you didn't answer.
Natke: Sorry, I missed your call. I had no signal.
Peter: I was about to leave you a message. Do you want to go to the cinema?
Natke: Sorry, my phone has low battery! I'll call you back!