Standard bank mobile's bad service

I have a contract with standard bank. My phone got ****** and it was insured. I need to get a ITC number and now standard bank is telling me the can't provide me with the ITC number. I phoned them numerous times to block the phone and they keep on telling they are unable to block the phone. Now they expecting me to pay for a phone that I no longer have and my insurance is not going to pay out without the ITC number. This is really really bad service. I have tried now for more than 2 weeks just to get the phone blocke. They keep on insisting that I did not put my standard bank sim card in the phone, but I only have one sim card for my two phones. I keep on telling them that I only used the one sim and they making me a ****.