My question has nothing to do with facebook. message button on phone is lit up, push button to listen to message and it doesn't prompt to retrieve new or old messages just rings

SOURCE: Message light continually lit

There are different reasons your message light may come on besides voice mail calls. The situation that started the message light needs to be completed before it will go out. I cannot be sure on your particular phone but quite often when I see this problem on other business phone systems it is because someone on another phone in the system tried to intercom and there was no answer setting off the message waiting indicator. (This may require other buttons to be pressed by the caller making it a rare occurrence) If so, you may have to press the message button to return the intercom call. The trick is the other phone needs to be answered as well or the system will not shut off the MSG light. Are there any unusual messages, icons, etc.. on the LCD? If this is not the case, you MAY be able to force the light off by leaving yourself another message and then retrieving the message.

SOURCE: Fixing message isssue

You can also press #409 on the phone to clear the message waiting indicator.

SOURCE: phone rings many times with no answering message coming on and no messages recorded

I can't seem to get the security code entered.  It won't change.  None of the numbers will change when I try to set it up.

SOURCE: how do I retrieve messages left in the operator's voice mail?

If you pick up the handset and press the button it will call back whom ever left the message. (that extension you see.) If it is not the voice mail extension, it was just a request to have the receptionist call back. Doing so should clear the lamp.

SOURCE: NTL VS2000 cordless phone

Here's a link to a manual that includes the VS2000 handset.
http://www.telephones4u.co.uk/userguides/VS2003.pdf

Hope you find a solution.