As far as I understand it, you have 130 days to submit the documents. If you don't do so, they will permanently apply restriction on your account after which you can withdraw the available funds after 180 days of your account being limited.
They won't delete your account if you don't send the documents. They will just apply a restriction permanently which will restrict you from doing certain tasks such as sending money/withdrawing etc.
I would suggest you to send them the documents. If you want to use PayPal only for a while, submit the documents and when you want to close the account, you may do so.