main floor and official business: bar/club

2nd floor: brothel aka sexual services 

Black cat is officially a small bar that belongs to Alexander Moreno. In the past it supposedly belonged to a man named Leroy Boyle.
In the back of the bar however stands the mafia syndicat Razulshiten. The bar is just one of many stores where the mafia gets information about other groups or just a place to meet up and have fun. 

(Even within the syndicate only higher executives know that Black Cat belongs to Razulshiten) . 

The bar is untouchable in a sense since Razulshiten eradicates all problems around it, this not only includes rumors being shut down immediately and indefinitely, but also the people who suspect something or talk to much. The mafia is so big that there is no way for the law to track them down properly and law enforcers (eg. police) either are involved or are unable to pin down enough evidence.

The workers of Black Cat all signed a contract and NDA promising their absolute loyalty and silence. If the workers break their oath, they and the people they love will come to harm.

Alternatively: the workers of Black Cat are bound by contract and it's hard for them to escape the life of selling their body, because they are kept in debt  and many have been manipulated in a way that it is hard for them to get any other job because they lack qualifications or enough education.

The life of the workers can be easy or hard depending on their debt and their contract. Some only do the basic work of serving at the bar or working every few days or only on request. Others have to be there  almost daily with no sick leave.

Each worker has a different quota to fill depending on their contract, dept and popularity.

Next to entertainment they  also have to collect information from specific clients sometimes via “bed talk” which is dangerous should they be caught.

As for their living expenses and ways to educate themselves, it's all up to them to pay for it, or they are lucky enough to find a provider or Pateron(s). However even then, they still have to work at the bar to fill their quota, so most don’t even try. 

If they have trouble, there  is no obligation of the mafia helping them, but if they pay the right amount of money and/or ‘favors’ they can receive support.