HDFC Bank — NPS account frozen

Hi my nps account is frozen i had paid the first transaction through hdfc bank.
I got a mail saying "in this regard, we wish to inform you that your kyc was rejected by your bank/pop. We have not received the required documents as on 02-jul-2020.in order to complete your registration process, you are requested to submit the bank/pop verified enps registration form along with supporting documents (Like bank statements, etc.) to the below mentioned address."

Since nowadays sending document by post is difficult to the bank. Please provide a solution what is supposed to be done, any online solution to it.