Asking for ID Documents over WhatsApp - POPIA Compliant???

I am told Cell C are you currently running a promotion that gives customers a R500 virtual Mastercard voucher when upgrading and purchasing a new Samsung Z Flip 3 phone. This number being used to facilitate this promotion - ***. We were given this number from the Cell C branch in the Cresta Mall. I have enquired with Cell C and I am being told this number belongs to a private person. This is the automated response you get when you send a WhatsApp to this number….

“Change your world with Samsung and Cell C.

Thank you for purchasing a Samsung device with Cell C

Please submit the following documents in order to verify your purchase

Proof of purchase ID copy Device IMEI number

*Please note verification takes up to 72 hours, once verified you will receive a virtual Mastercard via WhatsApp within 48 hours*”

I am now told that this number may belong to a Samsung Agent in store. Okay if this is the case, I would assume they are NOT POPIA compliant. They are dealing with customer sensitive documents and are they being secured? This matter needs to be escalated to higher authorities in the business. Surely there should be a more secure way of facilitating all of this. Sending ID documents over WhatsApp is absurd!