property tax payment

The society has objected to the permission of change of user given by the administrator to one member under DC rule 51 in his tenure in 2010. The issue is still pending.Now the MCGM has sent the property tax bill under new capital value based system with the user category of the flat of member as commercial which means that the municipal authority has granted the change of user for his flat.In such circumstances what are the options for society since the property bill is in the name of society in Mumbai.