i hope whoever i speak to (her mom or dad) doesn't bitch me out/think i'm lying/ or hang up on me.
Just remember that you've done nothing wrong though! You can start out polite and then move on to bitchiness if it doesn't go your way. You could present it as an innocent miscommunication (even though you know it's not) -- try to get them on your side and they'll be more likely to help you.