A cease and desist letter may be either a nuisance, a serious threat to your business, or something in between.
Where a comparison of your product and the patent that has allegedly been infringed reveals no legal liability on your part, it is important to respond to the sender with a clear explanation of why their letter has been sent in error.
Even if there is potential infringement, it is important to fully evaluate your options up front in order to minimise the cost and reach a resolution as quickly as possible. There may be arguments that the patent is invalid, or a solution may reside in offering a reasonable license fee.
Patentable can help evaluate your best course of action, and offers a free no-obligation initial consultation.