Competition Risk - Seller's Relatives

I recently bought a company and we have a 5-year non-compete agreement with the seller. However... one of seller's adult children was released from working at the business prior to close. That person then opened a directly competing business after we closed. That person apparently has access to all our customer contact information, and is now stating his intention to sell competing services directly to our customer base. We have no non-compete agreement with this person or any of the seller's relatives.

I don't think we have any recourse, and plan to simply continue running the business to the best of our ability. But I wanted to share with the community to highlight the risk. (FYI, this is a sensitive issue with the seller, so keeping this post anonymous).