5 Days of emails disappeared from all folders

5 Days of emails disappeared from all folders

Hi, on three separate occassions one our zoho mail boxes has had 5 days of emails disappear.
Mails before and after the 5 days are still present in all folders.
This includes inbox, sent, trash.

This occurs weather we operate using remote imap clients or exclusivelu directly from zoho website.
So the dissappearing is occuring at the zoho server.

The trash holds other emails older than 5 days.

The dissappearing emails occurred again this morning. New emails kept arriving but all evidence of 5 days activity dissappeared. These are recent emails and do not meet any archiving rules (older than 3 months).

Attached is some screen dumps of some folders showing emails today and then a 5 day gap.

Please advise.