Useless Call Centre

I had an unfortunate experience of getting hijacked last weekend on Sunday morning early hours and my phone taken during that ordeal. So this morning when I called the CELLC call centre to block the old number after realizing that it's still ringing when I call it I was asked a million questions pertaining to the last airtime balance and last filled numbers!! Information which I no longer have recollection to after that terrible order of being hijacked. As we speak that number is still in use and call centre agent refused to assist me in blocking that number. What really needs to happen!!!???