I'm not sure I understand what happened here. ZG, it sounds like you did not apply for this job but they called you asking specifically about a job for which you're overqualified? Under those circumstances, I agree with mschrisgo2 that it's a waste of your time and theirs to interview. I'd call and ask if they are requesting an informational interview for other positions which might be available; if they are, then go. Who knows what could turn up? But if they're not, I'd pass. Your time is better spent pursuing appropriate openings, even elsewhere.