I think you should call the Ts office and talk to them about it before paying anything. The only free consult I've ever had was a phone consult and it lasted no more than 15-20 minutes. If she did intend it to be free then I think you're right in that she changed it from a consult to a full session because she went over the allotted time. If she confirms this then I would argue it and not pay the bill. As a professional who told you it was a free service, it was her responsibility to stay on schedule, not yours