Flat maintenance

Hi All, I recently bought a resale flat and the existing owner didn't pay maintenance fees for more than two years. while registrations I have asked that the seller regarding the due amount of maintenance and he said like am ready to pay the amount but the society incharge is yet to provide the proper maintenance bills. After I took over the society members reached me and said the existing owner have to pay the balance of maintenance fee. I replied like I can pay the maintenance fee from my take over and I cannot able to pay the existing balances. Since I aready asked the existing owner and he replied like he will be taking care of it. Also we have the mentioned in the registration documents if any issue related to this property the existing owner should be responsible for it. Now the society incharge is saying that you can pay the current maintenance and join members of owner association. But we are going to file the case against existing and current owner (mine) to recover the existing balances. Again I reached the exist owner. He is saying that I will be taking care of it and you don't want to worry about it.