NOT REFUNDING A FAULTY PART

We at Ceres Toyota ordered a part from Autos****, a nr we attained from Gumtree. They had a part, full payment was made and Autos**** couriered the part to us in Cape Province. We fitted the part, but it was faulty and did not work. We notified Autopart, they promised a refund (that was end of 2014). After calling once a week, they told us in January 2015 that we have to send the old part back to them for refunding. On 15.01.2015 we couriered it back to them. We made sure it arrived with them and asked for refund on a weekly basis. It is now 21.05.2015 and no payment has been done, after numerous promises that it would be done. Our banking details and invoice was mailed to them end of 2014 and they acknowledged that they received it then. The contact person that we talked to the whole time was Iggy, who always made promises, but never delivered. We now have to divert to these type of media to get payment as promised. We will use Hallo Peter and internet to take this matter further.