I tried to call you back today, but was told that you had left the office.
Tried to leave you a voice mail message, but no one in the office knew how to  transfer my call into voice mail.
They were good about answering your phone,  however!
I will call you tomorrow morning before my first meeting at 8:30.
If I miss  you, I will ask my assistant to interrupt me when you call back.
I will be  in meetings with operations people from London and Sydney tomorrow, but can  easily step out to talk with you.

Returning your call