Incoming calls being answered remotely by stranger

Hello, thanks in advance for any help.

I have a Galaxy S8+. I formerly used a Samsung Gear S3 smartwatch with it's own phone number, and I had the "Number Sync" feature linked to my phone. If you aren't aware, that is a feature that would allow me to answer calls on my watch that were inbound to my phone. Well after a year I decided I didn't need the phone line on my watch any longer, so I closed it.

Somehow, even though the watch no longer has an active phone line, and the Number Sync feature is disabled and the watch/phone are no longer linked... incoming calls to my phone are still being forwarded to the # that my watch used to have. The big problem is that # is now owned by a random customer not at all associated with me. So I have friends/family/co-workers calling MY phone, suddenly my phone displays a message saying "answered remotely" and they are suddenly talking to her instead of me.

I've called into AT&T support twice, and visited my local AT&T store twice. Nobody is able to help. I've been told to factory reset the watch, which I have. I've been issued a new SIM card.

This is a huge issue and I need some help.