Remove precious trusted devices signed into main ID

I am the Primary Account Holder. An unauthorized user on my phone plan previously logged into my master Xfinity ID and saved their device as a 'Trusted Device.' I have changed my password multiple times and turned on 2-Step Verification, but their app continues to bypass the login gate and actively streams my security cameras using their lingering session tokens. I need an advanced digital care agent to run a complete backend deprovisioning utility on my account and forcefully revoke all active OAuth / device stream tokens across the entire database registry immediately.