I took the encumbrance certificate from municipal office and on that still my name is showing as the property owner.
Does that mean real estate agents are lying or is the Land is under dispute according to the information provided by real estate agents?
You dont go by the rumours.
Since you have the registered sale deed in yor favor, you first take possession of the property.
You may put up barbed wire fencing all along the boundaries of your property to secure it properly.
You may even put a temporary structure in the vacant property.
If at all anyone else has also purchased the property you will get an objection from the so called buyer after which you can jump into legal actions to secure and save the property and safeguard your interests in the property.