Ridiculous Service and process

For the past month, I've been trying to blacklist my son's phone which he lost, and Cell C is asking the most ridiculous list of questions in order to provide me with an ITC number. Firstly I confirmed my details as his sim card is registered under my name. Then i was asked frequently dialed numbers.....right....i must go ask him now, my son, give me 5 of your friends numbers so that CELL C can check the details. I promise you this child will look at me thinking that I've fried all my brain cells. How can a company expect customers to remember all the numbers on saved on their cell phones. One of the reasons for having a cell phone is to save the number under someones's name for ease of reference should the need arise to dial that number. Now it's expected to memorize all your number on your contact list, should the need arise, you lost your phone or it was ******, in order to have it blacklisted and you want to claim from your insurance, but cant' do, as CELL C refuse to give me an ITC number as I cannot provide them with the last dialed numbers my son called, as I'm expected to know these number at the top of my head. This counts for him as well. This is seriously a joke.