two line system landline phone

I'm not seeing announcement only in the manual. I'd say go completely through the answering machine set up to make sure everything is correct. Also make sure it's your answering machine doing this and not the phone company voicemail. 

Thanks spoom2 for your reply. I think you may be right about that not being in the manual as I think I may have been looking at another manual for another phone...not sure. Anyway, like I said, this phone was working for 3 or 4 years so not sure why it would all of a sudden do this. The only thing I can think of that was done around this time was that I had completely rebooted my desktop computer which involved me unplugging and replugging in the Vonage box.

Oh and I did go online to be sure that the Vonage setups were set to voicemail off. I have never used their voice mail. 

I guess what I am asking now is that, is there any way that settings could just change simply from unplugging Vonage when rebooting computer?

Unplugging from your Vonage ATA shouldn't do anything to the phone settings. If you unplugged the phone from power and the batteries for the battery backup are bad or there's no batteries, I don't know what would happen to your settings as the manual really doesn't address that. If you've gone through all the settings and they are correct it could be the phone is just bad. 

Ok, update. We have solved the issue. Turns out that about a week ago, my husband decided to finally plug a phone into the garage after many years of not having one out there. He came to me yesterday and said that perhaps that is what caused the issue. Sure enough, turns out there is an answering machine in that phone as well. We turned that answering machine off and voila...problem solved. 

Thanks again spoom2 for your help and suggestions.

Glad you found the solution, two answering machines don't work well together, as you found out. Thanks for letting us know the fix.