Supersonic???

I joined Supersonic last year in September. Since then, I have received 1 invoice, with the incorrect name and adress on the invoice. After numerous calls, this is still not fixed. I pay money into their bank account without knowing what i owe them. Contacting them is almost impossible. "press star at any time, and we will call you back" also does not work, exept for one time when they phoned me at 22h00 at night, and then put the phone down when I answer. Worst supplier ever.