Hi togheter

Somebody told me he would have sent an E-Mail to us (info@mydomain.ch). But we didn't received it into that mailbox (info@mydomain.ch). So I checked the mail.log and I found the following lines:

Apr 5 16:57:02 zimbra postfix/smtpd[10441]: connect from x.y.com[193.xxx.xx.x]
Apr 5 16:57:02 zimbra postfix/smtpd[10441]: setting up TLS connection from x.y.com[193.xxx.xx.x]
Apr 5 16:57:02 zimbra postfix/smtpd[10441]: Anonymous TLS connection established from x.y.com[193.xxx.xx.x]: TLSv1 with cipher ADH-AES256-SHA (256/256 bits)
Apr 5 16:57:02 zimbra postfix/smtpd[10441]: 4BEBE36E48FE: client=x.y.com[193.xxx.xx.x]
Apr 5 16:57:02 zimbra postfix/cleanup[10445]: 4BEBE36E48FE: message-id=<1CE47E93197503498753DEB7C04208210121C04947@S-20014.x.z.ch>
Apr 5 16:57:02 zimbra postfix/qmgr[3220]: 4BEBE36E48FE: from=<x.y@z.ch>, size=10090, nrcpt=1 (queue active)
Apr 5 16:57:02 zimbra postfix/smtpd[10441]: disconnect from x.y.com[193.xxx.xx.x]
Apr 5 16:57:06 zimbra postfix/smtpd[10449]: connect from localhost.localdomain[127.0.0.1]
Apr 5 16:57:06 zimbra postfix/smtpd[10449]: 09C7536E49F7: client=localhost.localdomain[127.0.0.1]
Apr 5 16:57:06 zimbra postfix/cleanup[10445]: 09C7536E49F7: message-id=<1CE47E93197503498753DEB7C04208210121C04947@S-20014.x.z.ch>
Apr 5 16:57:06 zimbra postfix/smtpd[10449]: disconnect from localhost.localdomain[127.0.0.1]
Apr 5 16:57:06 zimbra postfix/qmgr[3220]: 09C7536E49F7: from=<x.y@z.ch>, size=10751, nrcpt=1 (queue active)
Apr 5 16:57:06 zimbra postfix/smtp[10446]: 4BEBE36E48FE: to=<info@mydomain.ch>, relay=127.0.0.1[127.0.0.1]:10024, delay=3.8, delays=0.19/0.01/0/3.6, dsn=2.0.0, status=sent (250 2.0.0 from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 09C7536E49F7)
Apr 5 16:57:06 zimbra postfix/qmgr[3220]: 4BEBE36E48FE: removed
Apr 5 16:57:06 zimbra postfix/lmtp[10450]: 09C7536E49F7: to=<info@mydomain.ch>, relay=zimbra.mydomain.ch[192.168.193.3]:7025, delay=0.28, delays=0.09/0.01/0/0.18, dsn=2.1.5, status=sent (250 2.1.5 Delivery OK)
Apr 5 16:57:06 zimbra postfix/qmgr[3220]: 09C7536E49F7: removed
That would mean, this mail should be in the mailbox "info@mydomain.ch" right? But it isn't..

How could I find out where the mail is stuck or even if a user already deleted it? (there are three users who can access this inbox).

Thanks a lot in advance!
P@sco