**** SERVICE WHEN BLACKLISTING PHONE

I called cell c from a landline because clearly I've lost my phone and I have no other way to contact them. They then went on to asking me questions like the last 3 numbers I called... How am I expected to know such? The numbers are obviously saved on my phone, I do not know them off by heart. Then I'm asked what my airtime balance was. Does any normal person check their airtime balance every few seconds? Third they refuse to let me speak to a supervisor since the agent says she doesn't know why this is done. I don't know why someone would want to blacklist their phone for no reason.