Order #*** – Sent wrong part, overcharged me, and now completely ignoring me

I ordered and paid R1,910.00 for a Chev Utility 1.4 CR9 Throttle Body (Order #***). Instead, Boss Auto Spares shipped the standard model which retails on their own website for R1,499.00. They have sent the wrong part and overcharged me by R411.00.I have called their office and was instructed to log a return via WhatsApp. I have been messaging their official lines consistently since Friday and am being completely ignored.This is unacceptable customer service and a violation of the Consumer Protection Act. I require management to contact me immediately to arrange a courier to collect this incorrect part and process my full refund