Trai — aadhar card registration — thumb impression

Address:

380013

My service provider is vodaphone. My question is for registration of adhar card can vodaphone insist for thumb impression on the true copy eventhough signature is given? How can they demand thumb impression? They have to verify the copy withe original adhar card. Pl reply and issue suitable instructionto to vodaphone authorities,
My point is very short. Adhar card registration for mobile number is necessary as per govt instruction. I am having a sim card of vodaphone. They are insisting for thumb impression on adhar card even though signature is given? My question is that has govt autorised vodaphone authorities to collect thumub impression of mobile owners?
Manindra vaidya