The cease and desist letter that you received was probably written by an attorney. The attorney can't outright lie to you, but they can spin the facts in their client's favor almost that far. Let someone who knows what they're doing and is on your side counter that. Determining whether or not a patent blocks your product and determining whether or not a patent is valid are both extremely technical, legal questions. That is why a patent litigation attorney during active litigation charges $500-$1500 an hour. We can help you determine whether or not you have a problem much more affordably. We can help you make that problem go away and if it doesn't go away we can connect you with patent litigators that can help you through the end of trail.