The application for the renewal of your residence permit has to be submitted to the foreign police in Slovakia before the residence permit expires. You will have to submit the application personally, you can hire a lawyer to represent you in the whole process but still your personal presence when submitting the application is required.
As you are both directors of the Slovak LLC (s.r.o.), you have to prove a net profit (after taxes) for the past year in the amount of at least sixty times the subsistence minimum – which is currently at least the amount of around 12.400 EUR. If you are both representatives at the same company, this amount remains the same for both of you.
The main reason when you applied for a residence permit for the purpose of doing business was running real business activities. If you had no income, that means that you did not run the business in Slovakia, which means for the foreign police and according the law that the residence permit renewal may be declined.
Also the residential address has to be real. The foreign police officer can go (and mostly they do) personally check the accommodation before they decide about your application. Accommodation can be proved either by letter of ownership as well as by the rental agreement.
The foreign police officers when dealing with your application will also investigate whether you were living in Slovakia for at least half of the year. If not, they can again decide to reject your application.