Hi Online - Worst Online Shop

I went to Hi store in Menlyn on the 1 Dec 2018 , the sales lady helped me purchase a TV online , a Samsung 50". On Tuesday the 4th of Dec 2018 I received a call from Hi Online & we managed to verify my TV licence , the lady promised delivery will be done in 3 to 5 working days . I called them on Monday the 10th Dec to find out when the TV was going to be delivered, the lady said she would escalate the issue on my behalf . My shock came when I received an email from Bianca Fester informing me that item (Samsung TV) was over sold & they could not honour the item & got a credit to my account . I was very disappointed at I was looking forward to enjoy my new gadget by then. So my reply to her was the they had to make a plan , order another one for me but all I got was an email from Tarryn Davids saying there was nothing he could do . How do they keep on saying an item is in stock if it's sold out ?? Like really so annoyed.