FASTag transactions alerts are sent by a SMS on the Mobile number registered while applying for FASTag.  In case you wish to edit or change the Mobile number for FASTag then please write to us at fastag.support@kotak.com with KYC document and dully filled and signed FASTag Maintenance Form. Click here to download the form OR You can register the request by visiting Kotak FASTag Portal  >> Click On Complaint >> New complaint >> General Complaint >> Request >> Request for change/update in Mobile Number/Email Id. Upload the dully filled and signed FASTag Maintenance Form and KYC documents in attachment option.