Telkom Billing Mess

Firstly i was misled by MobileTalk agent to signup a contract ,and after receiving the package , i realized that what they promissed me is completely different .Then i cancel the deal and they collected the device .But even if i have never used anything from them,(data or device) and the deal was cancelled, Telkom just billing me every month . Three Escalation reports but nothing have changed . It seems just impossible to cancel their contract .