As you might expect this kind of thing is fairly common @Betty3@? It sounds like you just need to change the password on the email account the former employee is fetching mail from? It probably goes without saying but do not send the new email password through email which the former employee has access. From there the smart phone connection for anyone without the updated password will error out.
My suggestion is always to create a strong password. I know they are a bit to input on a phone but you shouldn't have to do it often. Check out Create strong passwords. I hope that helps?
...turns out that my two cents is worth less or more depending on the current exchange rate.
roy darling *my posts seem a lot shorter in my head