Change of banking details

Want to change my banking details following my husband's death as the account now frozen. The policy is in my name. Was sent a form to fill out, done, and returned to them. Response : can't change banking details using this form. Go on line to do so. Attempt to do so - username, password not accepted. Call and complain. They agree to use the info. on the form and that they will confirm this has been done by e-mail. Never received. Nearing end of month. My vehicle, house contents won't be covered if policy not paid.