RICA ... only for select people obviously

I had the pleasure of getting a disgusting SMS from a strange number at Cell C. I felt absolutely violated and proceeded to phone Cell C to find out what I needed to do so that I could find out who had sent me this degrading and disgusting message. I was told that even if I had a case number there was nothing that Cell C could do because this was a prepaid sim card and was "pre-rica'd". Howcome this person utilize a sim card without having to provide their RICA information! What is the point of RICA if sick perverts can still manage to buy a sim card and get away with sending disgusting messages from it ! And Cell C basically throws their hands up and says well there is nothing we can do! I was offered no assistance whatsoever and do not believe that there is nothing you can do to find the culprit! I want a valid reason why RICA was not done on this sim card before the person was able to utilize it!