Asking your phone company about extra port out security could work pretty well, IF you make the added question/info something that no one but you knows, and that you will actually be able to provide when/if you DO want to change your phone account. I almost never use my actual personal information as answers to personal information question. I have a list of all the nonsense I’ve signed up with for various accounts, which no one else has access to. So if some site has a security question such as “Who is your favorite Aunt?” The answer is Commander Uhura or “7001 Penguins” or something.