Brand new modem linked to another account?
I just switched to Xfinity internet yesterday, and I'm trying to use my brand new Arris S33 modem that I just bought at Best Buy. The installation tech said he couldn't get it to work, and when he called the installation tech support line, the agent told him that the modem was already linked to another account and couldn't be used. He gave me a rental unit to use for 30 days which connected without issues. I tried a self activation again last night, and it still didn't work, and the live chat agents I got couldn't even tell me what the issue was; they just gave me the run around, transferred me to new agents, and then told me to call the automated help line that didn't address my issue whatsoever.
How is this even possible? This model isn't even a year old, so I highly doubt it's a refurbished unit sold as new, and Arris support told me this modem is in fact brand new and has never been registered. I'm going to return it to see if a new one fixes the problem, but I'm wondering if anyone else has had this issue with a brand new modem and if they were able to resolve it.