"Sorry, you have the wrong number..."

This weekend I was waiting to get picked up to go to work, when my cellphone rings. I didn't recognize the number, so I was hesitant to pick it up, but I did. "Hello?" I say.
All I got on the other end was heavy breathing. "Hello?" I repeated.

Then, the voice says, "Fred? 'That you?" It was an older man and he sounded very upset. "No, I'm sorry, I think you have the wrong number."

"Fred?"

"No," I said. "This isn't Fred, you have the wrong number."

The old man, obviously upset, does not give up. "Fred, I need your help...I need a boost...My car's dead..." He's sighing heavily, and out of breath.

"Sir, this is not Fred, nor does this phone belong to Fred. You have the wrong number," I said, getting irritated. At this point, I wasn't sure if someone was prank-calling me, or if this old man was actually in trouble. It's around 9 a.m. on a Saturday, and I didn't think that any of my friends would take the time to prank call me at that hour. It was really bugging me though. I was torn between  hanging up, or helping this person. I was trying not to laugh. This person simply wouldn't listen to what I had to say. Honestly, I don't even sound like a Fred.

What made it awkward is the fact that this person wouldn't acknowledge they were wrong, and would not hang up. I sat there on the phone, wondering when the appropriate time was to hang up. I didn't want to be rude...but I was getting a little mad, that he wasn't listening.

I ended up just saying, "Okay sir, I'm sorry, but this is not Fred. I have to go nowwwww....(slowly taking phone away from my ear... looking at it...and...click.)"

Awkward. Sorry pal, hope you got a hold of Fred.

By the way, I am a fan of the occasional prank phone call. Here's one done by Adam Sandler.