Wrongfully terminated?

[mhzrush]

What is the name of your state? Missouri

Hi, I know this sounds childish, but I was fired from Panera Bread two weeks ago for not completing my job (taking out trash) before I left. I'm a 20 year old college student.
(I tried summarizing the story as best as possible)

I arrived at work at 9am, was supposed to get off at 2pm. I told my manager that I had to leave at 2pm to pick my mother up, he said ok. The final half hour of my shift, the manager was cursing at me for no reason. I clocked out at 2pm and as I was leaving, he shouted at me if I didn't take out the trash I was fired, but I was off the clock and almost to my car.

I went ahead and left, and called the General Manager of the store. He said I 'abandoned' my job because I didn't take out the trash. One manager told me I was fired, the other said I abandoned my job.

(this is a little relevant) I was also fired 6 months prior to this incident for giving 5 hours notice calling off sick (the handbook states you only need 2 hours). I was told over my answering machine if I didn't come in I was terminated. I called the District Manager and let her hear the message and she got my job back and said you cant be fired over the phone.

I took my concern to Human Resources, told the man what happened, he said he would look into it and call me in a few days. When he called me back, he told me that since there was no corroboration that he was cursing at me, he was going to stick with the managers decision. He said that it was also irrelevant that I have had prior problems with the same manager. I asked him what the mangers decision was and he said it was to terminate me.
He also said that I was in direct insubordination by not taking out the trash, even after my shift is complete, and I should have 'known better.' I explained that I have never been late to work, and I don't have any write ups. He still said that I am terminated. I asked him if he would provide me a letter of dismissal, and he said that Missouri has no laws requiring dismissal letters.

I did some research and found out that there is probably nothing I can do because my employment is "at will". However, I have been harassed and wrongfully terminated by the same manager in a prior incident and supporting evidence.

I also did some research about dismissal letters in the state of Missouri and found out that if I send a request in a certified letter they are required to reply within 45 days.

[URL="http://www.moga.mo.gov/statutes/C200-299/2900000140.HTM"]http://www.moga.mo.gov/statutes/C200-299/2900000140.HTM[/URL]

Can I do anything about my termination? What steps should I take before I send a certified letter requesting my letter of dismissal? If my employer does not furnish my request, what steps should I take?

Thanks for any help