Duplicate cell phone numbers

<p>I have been receiving complians from people saying i am ignoring their calls, today i decided to take out my sim card and call the number and its ringing.</p> <p>I called vodacom and told them my concern and they are refusing that the number is not duplicated, my main concern, this is a contract cellphone, i am probably paying a bill for activities that were not even mine.</p> <p> </p> <p>I am really disappointed with Vodacom service.</p>