Other flat owners did not pay Full sale price.Staying without reg

In our apartment 17 residents are there. Out of that 6-7 people did not pay full price to the promoter and without registration they are staying in the flat. Say for example one person paid to the promoter only 10 lakhs where the sale price is 15 lakhs. So 5 lakhs are due. In this manner many people have dues to the promoter. As they are not paying the remaining amount so the promoter is not completing the pending work of the flat. So for that I am also suffering as I have paid the full sale price for my flat. I am not staying in that flat as some portion of work pending in flat also. When I asked to the promoter he is saying until the flat members do not pay the pending amount the promoter is unable to do any work due to lack of fund. And other hand flat committee is asking me to pay the maintenance cost. But I have told them that as I am not staying in that flat and you people did not pay the full price so for that I am suffering. Promoter is not working and making it complete. So I have denied to pay the maintenance cost. And asked that until you pay the pending amount to the promoter and promoter completes the pending work, I am not going to pay any money. Now my question is what can I do in this position? Did I do anything wrong?