Dismal, Supersonic

Supersonic has been dismal in every area of client service - to the point that we switched ISPs to a more expensive service provider, purely to avoid having to deal with Supersonic. Now, nine months after cancelling our services with them, I have received emails from Supersonic threatening to hand our account over to credit collectors for an amount that they raised AFTER the contract was terminated, for an allegedly unpaid balance from several years' prior when MTN transitioned to Supersonic (marked only as "Agility Transfer"). To date, Supersonic has not been able to provide a statement showing at what stage or for what reason the amount was charged to our account. For anyone considering Supersonic - unless you have an abundance of time and infinite patience to deal with their (numerous) shortcomings, avoid!