apartment number is missing for Internet + moving apartments

Hi, I already have Xfinity WiFi at my current apartment, but I will be moving apartments this week - I am pretty sure my building has Xfinity as mentioned by my landlord but

1) When typing in my address, there are only a couple of unit numbers in the dropdown, and my apartment unit number is not there so I cannot proceed - please help me figure this out!

2) I'm hoping I can keep my current plan's speed/pricing and just move it to the new apartment

3) not sure how moving works, ie. could I just easily transfer the address, will I have some slight overlap in service? etc.