how do i change the billing email address to go to our accounts dept and not my email?

Here is the link for changing the email address. See the section under editing your contact information. https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/manage-account-payment.html

To edit your contact information (1) Sign in to the AWS Management Console and open the AWS Billing console at https://console.aws.amazon.com/billing. (2) On the navigation bar in the upper-right corner, choose your account name (or alias), and choose Account. (3) Under Contact Information, choose Edit.

For the fields to change, enter your updated information and then choose Update.