Had this problem a while ago,y solution was either straight up tell them no, or to say you will do it for a fee and say I didn't get get all this information for free, it has cost me a lot to learn all this information and then to point out my degree.
If they didn't like it. That's not really my problem. I do not ow them my skills and expertise just because I know them.
I would help the ones I know wouldn't mind if I just said no, and ones that I know that if I helped them once doesn't mean I always will.
Consent is important and if they can't understand what no is and that consent can be taken away, then they don't really deserve the help I can give them.