First off, thank you all so much for your support and advice. I couldn’t believe the overwhelming amount of comments I got.
So, I decided to start putting together everything I could use to back up my argument as to why this was completely wrong. First off, yes I am so aware I completely messed up by giving such a big notice- will never ever ever do it again. That being said, I had only just mentioned that I was going to be moving and gave vague details of dates. My manager was the one who came to me the next day and told me she needed a written letter stating my last date. I had to figure out a date I figured would work just to appease her. I had no idea at the time, she was basically asking me to write a letter stripping my benefits as an employee. That in and of itself, feels very wrong.
Second, the handbook does indeed state that my discounts would be stripped the day I turn in my resignation. Where I think I could argue this (correct me if I’m wrong) is the fact that they would need written proof I read this/understood it. I have worked there twice. I quit and took a year off and came back. I don’t believe I signed proof of reading it after I had been reinstated. Could this be used in my favor?
Third, and this one is my strongest defence. Thank you everyone for giving me this idea. I had never signed an estimate for the surgery agreeing to the cost. Like one very clever commenter suggested, if I am being charged the client/patient price, then I deserve to have full disclosure of what I am paying. I was not given that and they do not have a signature stating I would be okay with the cost. We have every client sign one before a surgery, I believe I am also entitled to one. On top of my manager withholding this information all day long, I was also not informed from a legal standpoint.
I am not in any way a confrontational person, and I would 100% avoid a fight if I could. I feel like this is being forced out of me. My final bill has a “long term client” discount on it giving me a grand total of $40 off. I feel that I have no choice but to take this to the Big Boss above them. I just wanted to make sure I had a solid argument first. What do you all think?