Google now has its center in Mumbai and they are sending PIN very quickly within 6 to 10 days. As you said your PIN was generated 2 months back then request it for the second time and don't change the address.
Here is the solution, as you aren't receiving PIN, so it's better to verify by uploading aadhar card.
Now change the address and update the address in Adsense with the address that you have in your Aadhar card.
Follow these steps and change your address and make sure it is the same address as in your Aadhar card.
Open your Google Adsense account.
Go to settings option in the menu.
Go to "Account information" section.
Click on "Edit "
Update all the information and save it.
After 20 days, you will have the option to request PIN for the third time and then wait for more 15 days then you can verify your address with document verification.
Download CS Scanner App on your mobile and take a picture of your Aadhar card using this app and upload this picture and click verify.
You will get the reply from the team that your account is verified, this will take just a few hours.