Poor Service Deliver and Accusing Customer of Providing Incorrect Delivery Details

I have been waiting for Dawn Wing to deliver my goods for the last 2 weeks and still no joy. I made all payments 2 weeks ago and was informed delivery would be made by 19 July 2019. It is now July 25 and still no delivery nor a courtesy call updating me. I sent them a written inquiry on Monday 22 about status of delivery. They in response accused me of providing them with an incorrect delivery address and said my package was in Bloemfontein. I've used 1 address in all my shipments and have used Dawn Wing with all my previous 6 imports and the address has always been the same - East London and its stated on the invoice and clearing instruction. They promised on Monday 22 that they would deliver on Tuesday 23. It is now Thursday 24 still not a word from these people. It's not the first time this is happening. How do we hold Dawn Wing to account for this mess