Airtel Prepaid
Document submission

I m getting msgs and phone calls from airtel regarding submission of documents for verification. I m using this number since 3-4 years. When i msg to 121 ARC to know nearest store. I get reply that this is an invalid pincode.i ve checkd my pin code and sent msgs again several times. I dont know where to submit my documents.

and Why they require my documents again after 4 years.