"I thought I could come on here and ask for some help instead of being attacked for it. I have been doing taxes for over 15 years, yet never came across this situation and that is why I asked"

Where were you attacked?  Before you deleted your original post, you said you were doing a return for somebody that owned a schedule C used care dealership.  You didn't know how to report the revenue, you didn't know "what other expenses they could deduct", so basically you didn't know what you were doing.  I don't care if you were doing taxes for 100 years, if you were doing a return that you weren't competent to prepare, then you needed to obtain the competency or refer the client elsewhere.  There are certain areas of the tax world that I won't touch.  My ego isn't so huge that I am willing to put a client at risk just because I don't want to admit I am not familiar enough in those specific areas to proceed.  I have no problem not accepting work that I don't feel comfortable with.  As Dirty Harry once said, "a man has got to know his limitations".