You actually have two issues. The first is a possible ADA case and whether they terminated your employment so that they would not have to give you a reasonable accommodation
The second issue is a possible wage and hour law violation. It is against the law for an employer to not pay you for time worked. This is even the case when the time is not reflected on a timecard, provided that the employer had constructive notice that you had been working, such as by responding to e-mails.
You need to see an attorney as these cases can be complex.