OP & Broker Fee AKA getting screwed?

We signed a lease for an apartment. The apartment is owned by a management company. The apartment was listed on street easy by different agents, some didn't specify a fee while other listings listed the apt as no fee. We went through one that didn't specify so we could see the apt earlier and put an application in with the actual management company/owner. The agent then told us later that we owe a fee... She said we owed it to her company... The management company didn't say anything and then today we asked them about it and they wanted the checks made out to the actual building LLC (where our rent goes, etc). Are we getting screwed over? Are they trying to make us pay the OP (Owner Pays) fee that they should be paying?