Unable to cancel policy with auto & general! Don’t use them for insurance because you will never be able to cancel your insurance

My mom nominated me to close her car insurance policy with auto & general because she is in hospital ! I was told that I need to have a letter in writing from her that she nominated me to close her account! The letter was sent via email to auto & general as requested and I tried to call the following day(after 24 hours) to close the policy but I am told that they have not loaded the email to their system yet! How *********** can you be? I have been calling and I have been sent from one call center agent to another and nobody can help me! This is ridiculous!!