I'm not making any accusations, but here is one reason a property may drop suddenly in the ratings. Scroll to the bottom of the page and read the entry titled:
"How do fraud penalties impact the Popularity Ranking?"
https://www.tripadvisor.com/business/insights/hotels/resources/tripadvisor-popularity-ranking
TA staff have commented many times, that the best way for a business owner to contact them about their listing, is via their “Management Centre”.
1. Log in to the Management Centre
2. Find the "Contact Tripadvisor" box on the right side of the page
3. Click the "Get online help" link
4. Complete the form for your request
Best Regards