First Steps with a Patent Troll?

We're a small business where we invest everything back into R&D, so we're not sitting on huge cash reserves. We have a case just filed against us that is visible online but we're waiting to be served, for patent infringement. The company claiming infringement is known to us, they have been trying to get a foothold in our market for years, but their product hasn't found solid ground. We welcome competition as it drives a healthy economy, and we've got a really positive social standing in the community for supporting our customers and we're pretty highly respected by everyone. So when we found they had filed this complaint we were shocked. The complaint has no basis in reality as our product demonstrably does not implement any method of what their patent says, it will definitely be thrown out if it goes to court. But that's a stupid waste of time and money for us both. Has anyone had any success in writing to the company directly and showing how their case will lose, so they drop it and stop spending on something that will fail? We believe they filed out of bad faith because of jealousy and frustration against us. We've taken care never to speak against them or anyone in public, we know this is just sour grapes on their part. Obviously we're going to wait until we've been served but I feel that we can avoid further costs by sending a personal de letter to the owner of this company - I feel that they also have limited funds.