Sim swap problems

My partner who is a foreigner and therefore unfami**** with rica bought a sim card years ago which he has been using. He lost his phone several days ago and we went to the cell c branch to get sim swap but they were unable to help as it turns out his sim is rica'd under someone else's details. We tried anyway to phone the customer care line to see if they could help, and they then suspended his sim from being swapped obviously due to the fact that he is not the registered person on sim. So how does cell c not have a backup plan for such situations as i myself have experienced this before because it's so common to buy a SIM which turns out to be *******ly rica'd. I am able to provide regularly dialled numbers, bank statement to show it is linked to my partners account,and even willing to get an affidavit but cell c seems wholly unconcerned about making any effort to help. This number is also used for our business and we are losing a lot of business by not having this contact number available