Hello and welcome to JustAnswer. Please note: This is general information for educational purposes only and is not legal advice. No specific course of action is proposed herein, and no attorney-client relationship or privilege is formed by speaking to an expert on this site. By continuing, you confirm that you understand and agree to these terms.
I am sorry to hear about this situation.
1) Unfortunately, the employer does not have to pay you any more than the time you worked. Under the Fair Labor Standards Act, the employer may make deductions from an such an employee’s salary and determine a fair wage for the amount of time worked - see HERE.
2) You will hear "right to work" a lot. However, that does not mean what people think it means. All this means is that at time of being employed, the employee has a choice whether or not to join a union as a condition of employment. As such, this bears no significance on the employer's ability to terminate, unless a union contract that you are a part of specifically disallows termination without first a hearing, etc.
3) Reimbursements must be paid, however. If there is a written agreement/contract under which the employer owes reimbursements, then the employee must pay them, and they can be sued in court for them under breach of contract, promissory estoppel, and/or quantum meruit causes of action if they do not.
4) Note that under Fraelick v. PerkettPR, Inc., the Massachusetts Appeals Court ruled that if the employer fires an employee simply to avoid paying them reimbursements, then this can be a violation of COVENANT OF GOOD FAITH (firing an employee to avoid paying a benefit, for example), and can be basis for a wrongful termination suit.
Please note: If I tell you simply what you wish to hear, this would be unfair to you. I need to be honest with you and sometimes this means providing information that is not optimal. Negative ratings are reserved for experts who are rude or for erroneous information. Please rate me on the quality of my information; do not punish me for my honesty.
I hope this helps and clarifies. Please use the SEND or REPLY button to keep chatting, or please RATE when finished. You may always ask follow ups at no charge after rating. Kindly rate my answer as one of TOP THREE FACES/STARS and then SUBMIT, as this is how experts get credit for our time. Rating my answer the bottom two faces/stars (or failing to submit the rating) does not give me credit and reflects poorly on me, even if my answer is correct. I work very hard to formulate an informative and honest answer for you; please reciprocate my good faith with a positive rating.