Consult a lawyer for legal advise and start your search for prior art now, don't wait until a patent dispute arises. A lawyer may be able to work out a royalty

Consult a lawyer for legal advise and start your search for prior art now, don't wait until a patent dispute arises. A lawyer may be able to work out a royalty deal that is agreeable to all parties or he may be able to invalidate the patent with prior art. Either way having legal council is your best option for dealing with legal issues.