Network issue

I had 2 contracts with cell c where I was paying 3 phones, the other 2 I finished them last year and this month Im finishing the other one and I've never skipped a payment in this 5 years, my problem is that on the 1st of April my simcard just went out of service, I can't make or receive calls nor send an sms, I called cell c and they told me I need to buy a new Simcard that is not registered and make a swim swap, but every shop I go to they refuse to sell me a Simcard they say it needs to be ricad, I don't know what to do anymore coz I'm struggling now with my bank transactions and login into my student portal as I'm not receiving any OTP number. I'm very disappointed in you cell c as now I'm going to pay for something that is not working