Feeling trapped and held hostage by Supersonic Fibre

Since signing up with them I've had no service. I have had no router delivered. All calls logged have not been attended to. I've made almost 10 calls and get told they will get back to ne and nobody does. I was suddenly told I was in arrears and my service will be susoended yet I don't know how to pay and I've received no service. My internet cuts out every night for the last 2 weeks and I can't get a hold of them. I sent a request for cancellation and have received nobody contacting me. I just want to cancel and move to another ISP