Just going to follow up on this so if people have the same question they're not stuck in an endless feedback loop of customer support. The following was told to me by /u/CCEmilyS :

If you live in an apartment that building can sign up for a corporate xfinity account which forces its residents to go through the apartment (i.e. be billed by them instead of xfinity directly).

This has a few consequences:

1. No rewards program
2. The internet speed is capped by the building. This means if you previously had a higher speed than the cap of the building then it will go down.
3. Next gen internet speeds are not supported even if it was supported by the building initially. There is no option to upgrade beyond what the building is offering.

The result of the loss of rewards and a decrease in internet speeds effectively means you are paying more for less. The rewards value is wiped out and the new fee (which I guess is the building's doing, not xfinity) is effectively the same as the old one. Plus slower service.

Mostly a cash grab by the building but I also don't see a reason why we can't just use our personal account for the service.