How do I take a legal stand against unauthorized pay deductions on a weekly basis?

That is not exactly the law.  The law in Tennessee requires the employer to provide employees who are scheduled to work at least 6 consecutive hours with a 30 minute unpaid break unless the workplace environment allows ample opportunity for breaks. The employer is not required to deduct the 30 minutes and could provide it as a paid break. if the employer is not allowing you a 30 minute break, then in most cases this would be unlawful unless there is ample opportunity to rest or take a break.  Additionally, if the employer is not allowing you to have a break, then that must be work time which means the employer has to pay you for that time if you are non-exempt.  Additionally, the employer must pay all non-exempt employees for all time work.   So, whether you are getting a break or not, if you are being shorted 1 to 2 hours per day, then it is likely a violation of the law.  You should consult with an experienced employment attorney.