USA Spares Pretoria won't give me back my money!

I bought a water pump from them on 27 February 2021. I asked the sales consultant more than once if this is the correct part. On 28 February 2021 my mechanic said the pulley was different. On Monday 1 March 2021, we went back to request a refund (Purchase was made with Cash and under my business name). After jumping through hoops and sending banking details as well CIPC documents through on 01 March 2021, I get a phone call from the sales consultant requesting a affidavit from me cause the name on the Bank confirmation is different to the one on the CIPC. I am the Sole Director and do not have a business account. USA Spares now refuses to take my call. After logging a complaint with MOISA regarding unable to get a refund, did i notice the consultant had put the wrong name on the invoice. Luckily i have the WhatsApp screenshots proving the correct name that i requested to be placed on the invoice.