Dead phone and lost data Few weeks ago,my phone has suddenly dead and entered in an endless restart loop.
All data saved in the phone is gone. What I care for the most is  WhatsApp chats and attachments.
I remember I have backed up my WhatsApp chats few months ago ,but I do fail to remember what e mail I have used as I installed WhatsApp on my “late” phone 4 years ago and have changed my emails several times since then.
Is there any method to know the email on which I have backed up the info.
Or is there any method to retrieve the lost data ,escpecially Whatsapp Chats to my PC for instance ? 
Another question : Can I find the messages sent through this period.
Note: I don’t  know if my problem resides within the speciality of this website
Try replacing the sim to a different phone and downloading whatsapp in it. Log into the whatsapp with your phone number. It will prompt to retrieve saved data. Make sure you retrieve it otherwise it will be difficult. Whatsapp automatically backs-up the chats.