Sorry you're stuck but there's almost always a pretty easy fix! Do NOT try to start all over again, eg. uninstall Max's Pitch Package, etc. That can make things worse.
Before you post make sure you check the Help FAQ for an instant solution first. Then, if you can't find it there, you can post your problem here and we'll get to it ASAP (within 24 hours), but be sure you:
post in the right category
INCLUDE AT LEAST ONE SCREENCAP IN YOUR POST TO SHOW THE PROBLEM!!!!!!!!
explain the problem clearly
I have been working on lab 3B for hours and have redone it completely about three times now because it won’t grade due to the website not working. I have gone through every single step extremely thoroughly and I don’t know what could be wrong at this point. I’ll include my website link and the emails I have received from Salesforce! I hope we can work something out!
Yeah, that's addressed in the Help FAQ. The Flow you made is messed up. It's easiest to delete it and remake it, rather than try to fix it. Here's the link given in the Help FAQ for doing that:
https://www.maxzplace.com/instructions/how-to-delete-your-messed-up-flow-so-you-can-create-a-new-one-that-works