cease and desist letters coming from china? mwhahaha.. you can safely ignore that if you ever do get one.
when they cease making knockoff products from US Companies, then they have a leg to stand on asking our courts to respect them in any way/shape/form.
you have no contract with Hik', fuck em.. and Vendors dont remove Hik's logo, they buy unbranded white-label.. there was never any logo to remove.