They may not reverse a direct deposit if you did all the work for which you were paid, regardless of what you do later. However, if for some reason you were paid for hours or days which you did not in fact work, the employer may be able to reverse the direct deposit as to those hours or days, since you are not entitled to wages unless you actually did the work. If you didn't do the work, paying you was in error, and the employer may seek to correct an error.