cell c: Ridiculous and nonsensical security questions

I recently lost my phone and contacted cell c to block the phone.I was asked security questions which I was eventually told that my answers were incorrect.I found some of the questions rediculous and nonsensical. Question1: How much airtime did I recharge with and on what date? Question 2: What type of recharge was it.Question 3. Who are the last 2 people I called. I find these questions unreasonable for a person like myself who makes more than 10 calls a day.Who keeps a record of airtime recharges they do? And ho will I correctly know who I phoned last before the phone was lost. I was then told that there are no other alternatives to block my phone unless I get these answers correct.This is a bad service from this company and is unacceptable.I will get this sorted one way or the other and will stop using the network and advise everyone I know to do the same.