If you are an exempt employee, your employer cannot deduct for what is known as a "partial day absence." The fact that you are paid a salary, alone, is not sufficient to determine whether or not you are an exempt employee. You should speak to an employment attorney in your area to figure out if you have any wage claims.
As stated, a true exempt employee cannot be docked in the same way a nonexempt employee can for hours off or partial work days. it would be a good idea to meet with an employment attorney to see if you meet the definition of an exempt employee.