Not getting incoming calls

I'm switching from ATT to Xfinity.  I've spent over 2 hours with chat support.  I can make outgoing calls, but can't get incoming calls.  No one seems to know what's going on (chatted with 3 different people), but when I come to the boards, seems like it's a porting issue.  Who activates this?  Is there a number I need to call to find out if it was initiated?  Most people know my home phone number as that is all I give out and now I can't receive calls (goes into voice mail, but no voicemail).  I can't cancel ATT until this is over and now I'll accrue more charges from ATT.  Can someone help me?  Thank you!  This is for a landline, new to xfinity.