selling their wine? ... then a big company starts selling essentially the SAME wine, so they can't really compete with them and write them telling them to stop or they're going to attack them.. ?

This sounds very much like "The Mouse That Roared", except it was about a tiny European country in the 1950's that made wine. A California wine company began producing a similar wine, which would destroy the economy of the Duchy of Grand Fenwick. The country decides to declare war on the US, deliberately planning to lose, so they would get the huge amount of post-war financial aid the US always gave defeated countries after WWII. Unfortunately, the tiny squad of soldiers from Grand Fenwick got hold of a new bomb made by an American scientist, and won the war. It was made into a movie with Peter Sellers.

Search on google maybe you will find some results.