Well that's not correct. File a grievance and get the money that you are owed + penalty pay if applicable.
Central Region Supplement Article 12
Section 9—Full-Time and Part-time Employees
All work performed on the employee’s sixth (6th) day shall be paid at time and one-half (1 1/2). All work performed on the employee’s seventh (7th) day worked shall be paid at double time.
National Master Agreement Article 17
Other shortages involving more than fifty ($50.00) dollars for fulltime employees, and twenty-five ($25.00) dollars for part-time employees, will be corrected and the payment will be made available to the employee at his/her reporting location on his/her second scheduled workday after reporting the shortage. If the Employer fails to make the payment available on the employee’s second scheduled workday and the shortage was the result of the Employer’s error, the employee will be paid an additional amount equal to one-half (1/2) of his/her daily guarantee at his/her regular hourly rate for every full pay period in which the shortage is not paid after the second (2nd) scheduled work day, until corrected.