Oh the joy! I've switched to TrueVoip, an Australian company, who spent hours making DialDictate work with their service, and now I have reliable, clear dictation lines for the first time in two years.
Do everything you can to avoid BBP Global - their attitude every single time I've had a line outage has been that there must be a problem at my end (even though, coincidentally, all their lines go out at the same time), and not once have they made any suggestion as to what this problem might be or how to fix it.
I can't recommend TrueVoip highly enough - such amazing service and a terrific product - unbeatable combination.