Does the charge say it's for the room, or is it a merchandise location or restaurant? My credit card statements are always pretty specific as to what the charge is for.
I would start by trying to contact the resort to get the amended folio faxed or emailed to you, so you can see exactly what this charge is for. 407-934-5000 is the last phone number I have for POFQ. It should be easy for them to look it up and explain.
If you can not get any resolution by going through the resort, then I would dispute the charge with your credit card company. They will force Disney to produce documentation as to what the charge is and whether they were authorized to charge your card. Check your credit card statement carefully, because there is usually a time limit as to when you can dispute the charges and specific instructions on how to do it. It doesn't mean you won't have to pay if the charge is legitimate, but it is the best way to force a resolution if you don't get a response from Disney (but I think you will).