Sorry for formating, I'm on mobile.
So basically I am returning to a position at a seasonal job. I worked for the company last year and made 19.40 and hour (not complying, also we love a unionized workplace) and was really happy. This year, I decided to return to the company and in the interview asked about my wages because seniority was supposed to give me an extra dollar an hour (I talked with my coworkers the year before and they told me that's what happened for them); they quoted me a pay increase of 2 dollars minimum, so I would be making between 21.30-26.10 an hour. I was really excited for this and had other jobs lined up but due to the pay and my previous experience, I decided to go with this company.
Well, I was finally sent the onboarding papers and they are keeping my wage the same, which, when accounting for inflation means I'm actually being paid less this year. I emailed my supervisor and asked her why I would be making less than she quoted and she gaslit me telling me I must have confused the wage of another job interview.
Now I'm not sure what to do. I know my worth and deserve that increase but am not sure how to request a meeting to prove I deserve the extra pay. Any advice would be nice
TLDR: I was quoted a higher pay in the interview than what is officially in my offer letter. I contacted my supervisor and she told me I must be mistaken and that I would be paid the lesser amount. How do I bargain for more?