I just quit my job at GameStop after months of being mistreated. I was asked to bring in a letter of resignation when I bring in my keys. What’s the most “fuck you”, but professional thing I can do with this?

I was hired on at GameStop with the promise of 24+ hours a week (that's all I needed for my current situation). Shortly after getting hired, my manager parted ways. For 5 months, the store was run by a bunch of part time sales associates, from open to close every day. Then they hired a new manager and took him from his other place of work.

5 days later, we were given a week and a half notice that the store was closing permanently and we were offered 4 hours every week or two at another location. Then they proceeded to act like everything was fine and kept telling us to tell customers a bunch of BS that makes them look good, like we were only allowed to say “We were offered positions at other locations”. Anymore than that and we would get shit on.

So I searched for a new job, I started yesterday and shot a text off saying I quit and will drop off my keys today after I finish work at my new job. Today I got a call asking me to bring in a letter of resignation. What can I do with this opportunity?

Edit: I forgot to mention, this is all for minimum wage.