Counterfeit/Manipulation Policies

For the past couple of months I have had one particular listing removed or ended by ebay because they say it is counterfeit or I'm manipulating search results with a certain word in the title. I have been listing this item for at least 18 months and have had no problems then all of a sudden I'm getting messages for counterfeit or manipulating policy. For a start, the item is not counterfeit, and secondly, I have not manipulated search results. Every time this happens my sales drop dramatically. Coincidence?
When I do a search on this item, literally 100's of listings of the same item come up.   
Has this happened to anyone else? I have tried to do online chat and it's useless, they just follow the ebay line.

I don't know what to do. Can anyone give me information?