Why does the answering system announce the wrong day before playing messages?
This indicates that the YEAR is not correct for the phone's date/time setting. If the date is not set with the current year, the time stamp you hear before each message is played will tell you the wrong day. Consult your User's Manual for instructions on setting the date and time. Manuals for most models can found on this site. Click on the SUPPORT > MANUALS link, then search for your particular model.