Poor Service at Suria Motors Pretoria

My name is Sadeem Ahmed Rana from Durban. I was looking to buy a crank pulley for my BMW 330D E90. When I came across an advert on OLX, Crank Pulley for sale in Pretoria by Owner named Mohammed. Upon calling him and making arrangements for postage. I deposited money in his bank account. I sent him proof of payment as well. He promised to post it via Postnet as soon as he received the payment. Almost daily I asked him for the update whether it has been posted yet and he kept on stalling me and saying his father has posted it. Few days went by then I received the Postnet Receipt from him and I called Berea Postnet Durban to ask if they have received my parcel by providing them with Tracking number. They said they have not received it yet maybe it was just posted recently. So I decided to call the Postnet in Pretoria to ask whether they know when it was posted. Just for them to tell me it was posted yesterday. So I waited another day for parcel to arrive. I received an Sms from Postnet Berea, saying the parcel with tracking number ##### is ready for collection and I collected it the next day. Just for me to notice that Pulley has a gap and it's uneven. It will definitely wobble once it is installed on the car. So I contacted Mohammed from Suria Motors and explained the pulley is defective and he rep**** He didn't know that and he will speak to his staff. Today being Sunday I called my mechanic to install the pulley and we started the car and the crank pulley is Wobbling so bad. Mechanic had to remove the pulley. Therafter I have sent him numerous messages and called him but no answer. I have sent him voice note stating that the I would like my refund since pulley is defective. I have all the records of messages and Proof of payment. I am now waiting for Mr Mohammed to get back to me. Very dishonest indeed.