You might like to take a look
here and think about who should have your business as an ISP.
I'm in the process of transferring from Pipex (good 3 years ago, hopeless now) to UKFSN.
Flashing red lights do indicate something more serious than the ISP, though. Do you have ADSL filters in every telephone lead in the house? Otherwise, someone picking up a phone will zap your ADSL.
Once it connects, does it stay connected?