New Surfboard, US/DS always blinks

More than likely. I’d exchange it (probably faster than an RMA). 

Did you get the SVG2482AC? If so I’d probably look at something like the SBG8300. Its docsis 3.1 versus the SVG2482AC’s docsis 3.0. Many isp’s are pushing for the move to docsis 3.1 and that’ll give you a bit more time. Plus I think its cheaper. 

Unless you need the phone port. Then you’re a bit limited. 

Basically SVG2482AC is 3.0 DOCSIS  gateway with telephone ports , as you had mentioned US/DS light won't stop blinking, and also Xfinity can’t connect to it .

Have you tried self - activation with Xfinity App?  if still not working contact ISP to Re-Provision the modem .

Also. check if you had provided correct HFC MAC ID to the Xfinity at the time of activation .