Number theft

I have been on prepaid Vodacom for 17 years. My first ever sim card and number since 2002 has always been on prepaid. This weekend I accidentally lost my sim card and had to buy a new one - only to find out when I tried to do a swim swop that I am under some RMCS scheme with Edgars (that I never signed up for) and I cannot do a sim swop. I WANT MY NUMBER BACK - someone needs to sort this out - this is *****.