Worst online service provider I have dealt with to date

This is by far the worst service I’ve received from an online retailer in SA to date. I paid for an online order on 3 October but due to some system issue my order reflected as unpaid. After several calls and emails they only acknowledged that they received my payment 4 days later and my order was only dispatched the following week. When it finally arrived there was one item missing but nothing in the box indicating if the item was out of stock. I only received an out of stock notification later with a voucher to re-order on the website. However no shipping fee included, they actually expected me to pay for their mistake! I finally went in to their office at Parkhurst after telephonically confirming that i can come and sort the mess out there. Only to be told that they do not carry stock when I arrived. They had one excuse after the other for the bad service and agreed to send me a voucher for the shipping fee. I am still waiting - it is now almost 3 weeks later and I still do not have my product I paid for or the voucher they promised.