call the cable company....see what they say. maybe its everyone in your area...
have the cable company check all the lines from the street coming into your house. thats what i did, they replaced the lines and it worked perfect again
at the worst call the cable company. I know in my area it's $50 if it's your fuckup, but if it's their fault then it's free.
if you have all your shit on point and your sure of it, then call their ass. I know my friend called them once (he works in networking) and they found out that his wiring to his house was all sorts of fucked up.
Doesn't really sound like that's your problem since it worked before, but if you can find a way to blame it on the cable company (make sure your shit is straight) then do it.