SS is not releasing my line after canceling, no outstanding fees

Supersonic is not giving me further feedback on my previous Hello Peter review - issue still not resolved.

I have have cancelled some time ago, they said there is a missing payment, payment sorted out, I owe nothing to Supersonic, but not getting any feedback from Supersonic for the last couple of days to release my line, so my new ISP is not able to utilize the line as Supersonic is not releasing it.

Please release my line!