After purchasing the property, you should have got revenue records, i.e., the 7/12 records immediately to your name.
The four years time taken by the builder for this routine task is unreasonable and unjustified.
Even now you can directly approach the local tehsildar office with an application and copy of registered sale deed requesting transfer of revenue records to your name.
You can ignore the builder, but get back the amount you have paid to him earlier.
Once the revenue records are transferred, you can obtain the extract of the latest revenue records