Lost contacts after deleting an email account

I recently deleted an old account that is no longer in use as the phone kept asking me to enter the password for this account while the phone is in use. As a result of this I noticed that I have lost several of my contacts those were saved, I am not able to add this account back on my phone as the ID no longer exists. I would like to get the lost contacts back. Even though I can save them individually from the WhatsApp history, I’m afraid several other contacts may also have been lost. Hence, I am looking for a fool proof solution for this concern. Can someone please suggest a fix? Thank you.