Still waiting for online shopping refund

I placed an online order for delivery that took place 17 June 2020. Before delivery they deducted the money as per my shopping items. Upon delivery there were items that they did not have and thus the invoice amount was less R1000 and odd. I have been calling the call centre for more than a week of which they told me the refund should be done within 7 working days. I still did not receive the refund and in addition they are now passing the buck and saying that I should check with my bank? I checked with my bank and my banking app and there is no refund. I am seriously upset about this. What if I needed the money or those items desperately. I am appalled by this experience and will certainly never transact with them again. Whether online or not.