It is always proper to seek local advocate assistance in the matter though you may have to pay normal fees, as he is more approachable and accountable for his consultation.
1. The mutation is not a title deed and it is only a revenue record to show in possession. Once EC and the clear title deed is there, at the most they may demand you mutation charges from that date of your previous seller to this date of your recording mutation entries.
2. Please go through such direction. One has to pay property taxes before mutation on that property.. Who has paid is not the issue. Whose name is appearing is also not the issue. The mutation is different, property tax can be paid by anyone, but that amount goes in the account of the name of the owner as registered in their books.
3.A piece of advice was already provided, , do not take anything granted on your own on hearsay or postal guidance and when investing huge amounts, always take a professional advocate into confidence.