Sorry, you've suddenly lost access to your voicemail on the house phone. I can understand why that would be a concern, especially if you've been waiting for important phone calls or missed any from family and friends. I'd be happy to take a deeper look into this for you.
You mentioned that you have V-Tech cordless phones. Can you try pressing *99 from your one of the handsets (preferably the main one) and let us know what happens? For a list of other voicemail options and descriptions, check out this link.
If you're still experiencing issues, feel free to send me a quick private message and I can take a deeper look into this for you. To send a private message, click on my name, "ComcastChe," and then click send a message. Please include your first and last name and account number.