Poor after purchase customer service

On completing a cash purchase of a vehicle, I picked up an invoicing error which the sales manager alluded to and promised my refund of the difference. It's going into the 2nd month of today, tomorrow promises. Below is the note to the Dealer Principal and Customer Service. The dealer principal addressed but this remains unresolved. Good Day @'Sphiwe Manana' It is with the greatest disappointment that I need to re-address this outstanding issue, with you and your team. I have not received my refund, and feedback is non-existent from you and your team

Please advise further on my refund.