Hello. I need some advice. Last year, I took on someone at work to mentor to help her with a promotion. She and I are both part-time and don't have many overlaps at work so the process has been slower that we both would have liked. I just need to go over some procedures that she has to know in order for the promotion. I offered to meet with her outside of work to go over them, but with our busy schedule, it hasn't been possible.
Fast forward to present day, our company is eager to promote people (so I'm told) so our supervisor was asked by his supervisor who was next in line for a promotion. Our supervisor said it was my mentee and both of the supervisors signed off on her promotion paperwork. My mentee told me that the paperwork was signed off and she started to sign off on her portion of the paperwork in front of me. I told her not to sign off on them as she doesn't meet all the requirements mentioned on the paperwork for the promotion. I pointed out all the procedures she didn't know and she admitted that she didn't know them. The next day, I told my supervisor that she's not qualified for the promotion yet. My supervisor said that he didn't know that she didn't meet all the requirements. I thought the promotion was held off as she would need one more supervisor's signature for the final step. The next thing I know, the third supervisor signed off on her promotion and she has now been promoted to the same title as me.
I was furious when this all took place and gave myself a few days to cool off and now, I'm mostly disappointed in my mentee for lying on the paperwork and feel disrespected.
My question is, what is my next step? Do I complain to my supervisors? Do I talk to my mentee? Do I suck it up and go on? Do I look for another job? Do I take this up to HR?
I have so many feelings about this that I don't know where to start. What should I say?