Make sure that between now and then end of May when your hearing is that you continue to certify for weeks of benefits, so that if you were to win your hearing, you'd be back paid for these weeks.
Now, the big question. Are you relatively sure you make mistake that caused the cash shortage? Is there any way you can prove you did not? You were there that day, you worked, they can prove there is a cash shortage in your till, right? So it's logical to assume you were the one who made it, right? They have something they believe shows you paid out a ticket for $xxx amount of money instead of collecting that amount of money? Because this doesn't come up to the exact amount isn't really important sounding to me, its possible there was an $8 mistake elsewhere. You said it took them 7 days to find it...but obviously they did find something.
True, the burden of proof is always on the employer that they had good valid cause to terminate you for misconduct. But that doesn't mean they have to beyond any doubt and with video absolutely prove that you did make the error. It was a very reasonable error for you to make in your job, they have records showing the shortage. The unemployment office is not going to require a really high standard of proof to accept that the shortage actually occurred.
Whether you did it due to malfeasance, misconduct, carelessness when you should have been paying attention, deliberate misconduct ( you put the money in your pocketbook) something like that would be misconduct and a valid reason to terminate you. That you were doing your best and you made a mistake anyhow is not misconduct. If you were talking on your cell phone, not paying attention to what you were doing, goofing around with other employees while you made the mistake, that could be negligence on your part. If you'd blessed a friend or family member with this $300+ they should have been paying in and you paid them out, that would be misconduct.
There doesn't seem to be any reason that you should try to argue that you didn't make the mistake or to demand that you see proof that you made the mistake. Because you certainly can't argue, in light of the missing money, that you did not make this mistake unless they can show you tape of you making it.
It would appear to me that your best bet would be to take the tack that yes, I did make mistakes occasionally. Everyone does, even when doing the job to the very best of my ability. It was impossible for me to avoid doing it. I wouldn't have done it if there were any way I could have helped it. I was following, to the best of my abilities, the accepted procedures for doing the job.
Also, I had been doing this job for xxx amount of time and in that time, I had only had one previous occasion where I did this, and that was back in 2008. There had been no problems since then until this time. It might not hurt to show that since then, you were laid off, and what when you came back, you have had to go through a probationary period, and so at this time, you are considered a probationary employee on this job. So previous mistakes from your previous interval of working here should not really be considered a previous write up. During this period of employment, there have been no previous write ups or warnings.
You understood that you were being watched, that they can probably prove you made the mistake, and you are happy to try to pay the money back if they would let you. You did not want to lose the job, and you always did the job to the best of your abilities.
Now, that said, I think it is questionable to bring up the "I slipped and fell and hurt my knee, but I didn't say anything to the company."
I wonder, myself, if you said anything to anyone around you at work, or if they saw the slip on video? If so, it may actually have been a reason they fired you. Legal for them to do, but can help you get approved for u.i. perhaps.
Was there something in the rules of the company that said you would definitely be fired if there were more than two incidents of cash shortage? Had you ever seen anyone else who worked with you fired for having a cash shortage? In other words, were you always told since you've worked there that a cash shortage could be a reason to instantly terminate an employee?
I'm trying to determine if they may have treated you differently because they were trying to get rid of you--think through this angle very carefully before the hearing.
By not reporting the accident at once, you played completely into this scenario, and there is nothing in the world you can now do about it except try to get your unemployment approved. In some work situations, failure to report an accident is a misconduct reason to terminate, so as I said, you'll have to decide carefully how this should be handled. But if it does have anything to do with your being terminated for this shortage, you have nothing to lose by bringing that up in the hearing.