this happens to me when it teams with rain. my internet has been like it for three weeks. they will run you around and say the fault is with your house / your hardware. i had to go to town last year when it happened then - just like now.
the answer i got is the "pit" which is in the street gets full of water and the hardware has been trashed. they don't want to spend money on this as adsl is old tech.
I'm at the stage it's easier to go mobile broadband with someone like ovo or belong. do you need a phone line really..every one just uses mobiles these days
We'll need more specific information to be able to try and help. What type of internet connection? What other troubleshooting have you tried? What suburb/postcode are you located in?