Mutation Issue: Promoter Deceased, Tax Due

I purchased a flat in a G+2 residential building from a promoter who is now deceased. The land belongs to another person who is still alive, and the entire property is still assessed in the landowner’s name. The promoter did not complete mutation in his own name or provide any sanctioned building plan. The building has 6 flats in total. Currently, the KMC property tax shows a total outstanding of ₹55,500 for the whole premises. I want to apply for mutation cum separation for my flat by paying only my proportional share (₹9,250), but I am not sure if KMC will allow that. The landowner is not cooperating either. I need legal advice on whether I can proceed with mutation, what rights I have, and what legal steps can be taken to secure my ownership and protect against future problems.