If you have purchased a property by a registered sale deed, then you become the absolute owner of the property provided the vendor had marketable title to sell this property.
After obtaining the registered sale deed, you may apply for mutation of records in your name on the basis of the the registered sale deed directly with the Tehsildar's office.
You do not have to depend on any advocate for this purpose.
An advocate does nothing than to just act as your messenger. You skip or ignore him and approach the Tehsil office directly and get the mutation work done on your own, you will find response if you approach directly with an application for the purpose.