Billing and cancelation

I have canceled my contract as i dont want to upgrade. So we got a new invoice stating we owe 2166.78. my contract has still not been stoped. phoned the call center and no response . i would like a manager to contact me and tell me what is going on as i will not pay a cent. my last payment was december and now i get new invoices.<br> <br> acc nr ***<br> tel nr ***<br> <br> Hope now i wil get someone to attend to my problem.