the same thing happened to me.  set up a move but they never called me back. when i called, they had no record.  unfortunately i did give them my SS# to set up new service. they put me on hold for 25 minutes and then i eventually hung up.  

Called about an hour after I put in a transfer of address order.   I didn't answer at the time but Googled the number, and this thread came up.   I called it back anyway and was able to set up a transfer of service to my new address.   It is correct that it doesn't resemble regular Comcast, but it is legit.   I called the Comcast number today I was sent in an e-mail before the call from this number came through 5 days ago to confirm the transfer and they had all the information that I had given the person at this number 5 days ago and that the order had been completed.

I'm moving and expecting a call back from Comcast.
This number called me, but when I answered, they hung
up and said nothing.

Be careful with this because they called requesting my husbands social to confirm the move but my husband isn't the one under the account, it's me! Thank god I couldn't remember the social and just happily give it to them. I tried calling them the day before our move to confirm the move again and the ringtone and call wait music isn't the same as regular Comcast! So I called the  regular comcast number (1800-comcast) and they did not have any information of my move.... So DONT GIVE THIS NUMBER YOUR INFO!!!!!

Comcast number to transfer services to a new address.

This is Comcast/XFinity, specifically their customer service line that helps with people moving/transferring their services.