If it is already 3 years that you have submitted your details, it may be possible that your application has been rejected. Unfortunately they don't inform the citizens about rejection. You will need to verify whether your data has been submitted to the concerned agency. Here are a few details on how to contact the UIDAI -
Voice call - UIDAI has a Toll Free number 1800-180-1947. Try to contact the customer executives who may guide you on the actions to be taken.Fax -080-23531947By Post
P.O.Box 1947,GPO, Bangalore-560001Email - firstname.lastname@example.org
You may also find the status of Aadhar application on UIDAI portal here -https://resident.uidai.net.in/web/resident/check-aadhaar-status . You will need to submit your enrollment details and the exact status of your application will be available. If the application has been rejected, you can take a printout of the info from portal and show it to the concerned authority so that you can re-apply.