UNAVAILIBILITY TO COMMUNICATE OTHER THAN VIA PHONE

My Father sold his vehicle before he passed away, I tried to cancel his policy but was told I can't do this even though I can send them a death certificate and proof that vehicle is no longer in his name they will only do this once I receive Executor letter, in the meantime they will be collecting money on a vehicle that is no longer in his name. I was given a email address to send the paperwork to but the email address does not work, you can only communicate with Outsurance telephonically so not sure how they going to get relevant paperwork.