Poor service, no customer service and money making scheme

My new phone was ****** early this year and I reported to cell c requesting them to close the phone they failed to do that and I've been trying to do a Sim swop with no luck because the stores is closing at 5 and I'm knocking off at 5. I only learned recently that you can do it over the phone and it will be deducted from your monthly installment. I tried doing the Sim swop yesterday and surprisingly I failed authentication question twice, same thing today and when I tried to phone again I'm told i can only do the Sim swop over the phone within the 60 day period. I'm paying for mahala since they failed to block the phone and I'm loosing so much data because they are failing to do a Sim swop. That is really ridiculous.