Need clarification

Hi

I bought a flat in Bangalore around 10 yrs back and have been staying there since then. Recently the land owner from whom my builder bought this land and constructed the apartment and also sold it us, has got a legal notice that the sale of land to him is not valid as one of the sons who was a minor at that time has a filed the case. The legal notice has come to all the owners of the houses of the apartment. What should i do and how to go about this.

please let me know.

thanks