Towards the beginning of the movie, after Peter and his family enter Wendy's house and go to the room with the big window, Peter is talking up a storm on his cell phone and his wife throws it out the window. The dog picks it up, tosses it into a hole and starts to bury it. The phone is still OPEN and you can still hear Brad talking.

At the end of the movie, Peter jumps the fence to his backyard, says hi to the dog and hears his phone ringing. He digs it back up and OPENS the somehow CLOSED phone to talk to Brad some more.

The phone was open when buried and somehow closed itself while taking a dirt nap for those few days Peter spent in Neverland. I really doubt the dog dug the phone up only to close it and re-bury it.

Same thing with the antenna; it was buried at full extent but unearthed retracted.