I have always had points discrepancies corrected by e-mailing the hotel directly. It's a 100% success rate for me going that route. I don't even bother trying to go through Accor support for that. If somebody at the hotel told you otherwise, then you got a poorly trained hotel staffer, and you should try again with someone else. When I'm staying on Fairmont Gold, I typically just email the Gold concierge team, and they handle it, or I contact the Front Office if I have their e-mail and the regular concierge team if I don't, and they will deal with the front office staff.

Unfortunately, I've been told that the process of points calculation is still very manual at many properties, but it usually resolved quite easily and quickly.