My name isXXXXX'm a licensed attorney. Glad to try and help out.
Sure sorry for the circumstances, truly. My heart goes out to you.
Accordingly, I'm pleased to try and provide you with peace of mind. I've been in upsetting work situations and I know just how stressful they can be. However, here is the best asset I can provide you when it comes to your meeting. Namely, arming yourself with the knowledge of just what constitutes the legal definition of "insubordination". Specifically, it works like this under New York Law. Courts have held that the word means: "[a]n employee's failure to comply with an employer's reasonable request ... ." Matter of Guagliardo v. Commissioner of Labor, 27 A.D.3d 866, 867 (3d Dep't 2006); Saenger v. Montefiore Med. Ctr., 706 F. Supp. 2d 494, 508 (2010). However, looking deeper into the law, we find that it's no easy trick for an employer to meet that definition. In the first case I mentioned, the Court held that a physician was properly terminated from employment for committing a "multitude of serious, independent, documented, and therefore good-faith complaints" -- pretty strong language, as you can see. And the Court was referencing highly unprofessional and objectionable conduct such as blatantly refusing to attend to patients waiting in a clinic setting.
So, I say all of that to make this point. Your actual "real" designated manager was coming in later in the day. A fellow employee telling you to do something does not meet the definition of an employer's reasonable request, period. There are two factors here, meaning (1) your conduct was not sufficiently improper and (2) the person making the demand was not, in fact, your employer. Mentioning all of this presents your best chance of explaining your position. I'll hold a good thought for you that the meeting goes smoothly!
If you have a follow-up question or need clarification, please just say the word by using "reply" to reach me.
I truly hope all works out for you.