This is pretty horrible, but as a teenager when I was broke and starving I got free pizza a few times from different pizza places by calling and saying...
Me: "Yes, I would like to order my free Pizza"
Pizza Place: "Um, ok...did you have a coupon or..."
Me: " No, the last time I ordered...I asked for a pepperoni and your driver brought me a cheese pizza...Instead of driving all the way back and getting mine, he said he would put a free one on my account for next time"
Pizza Place: "Oh, ok...whats your name and phone number"
Me: * I tell them"
Pizza Place: "Hmmm I don't see any notes from the driver"
Me: "Well he forgot my pizza, I'm not too surprised he forgot to add the note to my account when he got back".
* Now at this point...they will either agree and send the free pizza...or they will argue a little more to when I would ask for a manager. If the manager would get on the phone, I would get more "agitated" and assertive, but stay courteous. I would explain that it wasn't my fault that they screwed up my pizza, if I'd known this was going to happen I would of made him drive all the way back that night and get the pizza with the toppings I ordred.
The manager would then approve, and if they didn't I'd raise it to the next level, get pissed and reiterate the situation " So your telling me I order a pepperoni pizza, paying for the pepperoni and your driver comes to my house with just cheese....screwing me out of the toppings I paid for....and then he weasels his way out of having to drive back and fix his mistake by promising me a free pizza that your now telling me I can't have? How many people has he done this too? Does the owner know about this".
And at this point...I would get the free pizza lol
Whats really funny, is that when I started dating my wife...we were all drunk one night and none of us had any money on us and I jokingly said I could get us free pizza, and then laughed and told the story.
My wife was shocked and said "YOU'RE THE GUY THAT USED TO DO THAT! WE ALWAY THOUGHT SOMETHING WAS FISHY ABOUT THAT BUT COULDN'T PROVE IT" lol turns out, she used to work there at the place I called a couple times...and it was her on the phone I was talking to, before I ever even knew her LMAO. Crazy small world.
Disclaimer: I don't encourage doing this. I was young, dumb and starving.