Black Friday special

I app**** for a Samsung A8 at 00:30 on black Friday 23/11/2018 morning which was part of the Black Friday promo for R249 p/m. I was called at 09:08 on the same morning to confirm and complete my on-line order. I later received news that I was approved for the new contract. I was also debited for R249 the following day. On the 28/11/2018 I received an sms from Telkom saying that I will receive my order in 3 to 5 days as it will be couriered to me. Today the 04/12/2018 I received a call from a consultant at Telkom saying the they can't deliver the phone as they do not have stock and I must rather take the Samsung A6 for the same price. I am very unhappy with this, firstly because I app**** for the Samsung A8 within an hour of the online black Friday sale on the Telkom website, and secondly you offering me a downgrade to the phone a app**** for. When the call centre agent called me initially to confirm my application on black Friday morning he mentioned to me that I was within the first 500 customers to apply so I would be getting a Samsung headphone for free. I don't understand how Telkom advertises a phone on Black Friday yet have no stock of it and why is Telkom substituting the special for a lower model phone.