If you want to be sure you don’t lose any contacts, you can export them to a file. ..
If you have a backup of your contacts, you can go to settings and import them. If not, you can do a few things. One is to use a third-party app like Find My Friends or Find My iPhone which will find your phone and sync the contacts from your phone to your email account.
The contacts in your phone are stored on the SIM card. When you delete an email account, it removes the contacts from the inbox of the email account. If you want to keep these contacts, you can export them before deleting your email account.
