MTN I NEED MY ITC NUMBER

I’m very frustrated with their service I’ve been calling MTN for the past 2 weeks ,I need to block my ****** phone and they told me to go to one of their branch of which I did ,and I have been waiting for three days for them to email me my itc number so I called their 135 number again for 2 days they tell me the phone is not white listed and they are still sending me to the branch ,the insurance company need that itc number . I’m not sure if they know of what they are doing.