Condo association board imposes and collects on outrageous late fees

We own a NYC condo apartment where the board is sponsor controlled after 8 years. There are two other unit owners on the board, however, they both reside in other states and both of their units are up for sale. The sponsor obviously has no plans to hand control over to the owners and continues to hold more than 50% of the units in the building, renting all except one. He has failed to obtain an OC thus far due to multiple violations in the building. He treats the building as his own sandbox and the condo money as his own.

Here's my immediate problem. While the condo bylaws define a comprehensive late fee schedule, the board (ie the sponsor) saw fit to compose a set of "house rules" that implement a completely different schedule of literally obscene fines which he claims is legally binding and overrides the condo bylaws. The property manager, a well known company, sides with him on this issue, (on all issues as a matter of fact) and makes a habit of marking timely payments late. All attempts to reason with the property management company are initially ignored and finally result in threats and invitations to pursue the issue in court. If I were to be blunt I would say that the sponsor and property management company are a bunch of brazen thieves.

My question is the following: is the property management company at all liable for this? The only thing holding us in the building are more than 50k in late fees that the property management company has generated for the sponsor.