I'd like to take this opportunity to welcome you to our forums and say that I'm really sorry to find out that your phone line is causing you a bit of trouble by not allowing you to make any outward calls.
I've run some checks on the line, and couldn't see any issues, so I spoke with our second line guys and they took a look at the line at switch level. They did make a couple of changes to things, so could you please check the line again. Should you still not be able to make any outbound calls, then I'd have to ask what happens when you try to make a call, and if you've been able to try another phone on the line.
With regards to picking up your voicemail messages, you just need to dial 1571 and then follow the options to listen to your messages.
Please let me know how you get on with the phone calls.