As you declared that you were making changes, if the insurer didnt ask what, thats their problem. They can refuse to increase the cover, and can exclude the new items and levels as not part of the original contract. Run with the existing cover. Tell them you do not want them to cancel the cover. (the message says 'unless we hear from you... so implies theres a route). Agree those exclusions for the time being and insure elsewhere from renewal.