Can't do sim swap

My sim card does not work, it says invalid and I am trying to do a sim swap for 2 weeks now, I called the call centre but they have to call me back to make sure it is me. After a few days they called me, but I missed the call because I was busy with a call on the office phone. I called them back to explain I missed the call and I gave my reference number and it is now more than a week and no-one has called about the sim swap. I send to emails to customer services, they called me back to tell me I must wait until someone call me about the sim swap and that I must be available when they call. How difficult can it be to do a sim swap??? I can't wait to cancel this contract, but they don't even want to help me with that as well.<br> <br> I have got 3 reference numbers ***, *** and ***