Hey Mc80,
Welcome to the community and thanks for taking the time to post here on the forums.
I’m sorry to hear of the issues that you’re having with your online account access, did you change your email address to be the primary address on your online account?
Bills would be sent to the registered contact email address that can be different to the online account login information.
Have you ever been able to access your online account since you took over the account from your ex wife?
Kind Regards,
Steven_L