My passport returned to ottawa

Hello every, i was away for work and my passport was sent through Canada Post and after 15 days it was returned to Ottawa. I used the tracking number to see where it is, and i showed me that on the 29th of July it was received back by sender.
I have called the passport number but lines are busy not even a chance to talk to any one.
Can i just go in at ottawa and wait there to pick it.
Do you guys think i can get it there or they will send it back again, and how long will it take if they do.