Hi Bro, i hope you are doing well. I am very happy to have an person like you who answers every simple doubts and questions. I really thanks you this.
My question here is recently when i check all my old msgs in whats app are not available msg are availble only from the day when i start using my phone. But iam very sure that i have seen all the old but now i dont find this messages. Please find the screenshot
Welcome bro. 
will do my best. Recently I got similar issue reported by our fellow user too. old messages getting deleted in his whatsapp application. this could have happened due to some bug bro.
DId you transfer whatsapp or switched between regular to business whatsapp version by any chance?
No bro i didnt switch to business. Recently i uninstall the whats app and again installed restored it yesterday only i noticed i have msg only from the day where i activated this mobile. Rest all gone. I can view the msg but when i enter no msg is visible
Did you restore from iCloud Backup bro? because based on when the last iCloud Backup happened, we will be able to restore only upto that date backup.
Was the iCloud backup you restored displayed any date about whatsapp backup bro?
Yes Bro but the backup has all the old msgs few mths back I had an issue so took the phn to service center they reset the phone I install WhatsApp again at that time I see all the msgs but resently I again restore what’s app again but now old msgs are all gone
Once we complete the restore, the existing backup will be deleted, bro. So, again, backup will be done fresh after a few weeks of usage. I think your old messages weren’t fully backed up with the last backup. That could be the reason you are not seeing old messages, but recently, messages have been intact.
When we restore again, we should check the date and size, bro. whether it matches the latest WhatsApp size or not.
Bro i have an doubt as we discussed earlier msg alone is getting missed all the photos videos which i sent are all available in media link and doc in whats app. If the backup is not restored properly how come the photos and videos alone available. Is there any option to retrive all the old msgs
hi bro, this could be due to whatsapp side issue. if there is a problem with iOS then we will miss data from photos app, messages app as well. but whatsapp is not reliable in storing huge amount of data. its always safe to take backup of whatsapp and not depend on it entirely for storing our conversation data.
so far no recovery option available bro. unfortunately.