Supersonic is a disgrace

Now it is 11 days since Supersonic canceled my services while M-web, Cool Ideas, and Cybersmart all claim, they can't connect because my previous ISP (Supersonic) is still holding my line hostage. Supersonic claims there is no outstanding bill to pay and the line is free, yet they are not able to provide a cancellation reference that Vumatel would need to pass on the line to the new ISP. In connection with all my other experience, I can't think of any other way than Supersonic trying this way to ruin other ISPs' reputations because their own is such a disgrace that they have to drag others down with them.