Pathetic preorder process

I preordered a Samsung S9+ from Vodacom Online and this was processed and confirmed by Vodacom on the 2nd and 3rd of March respectively. The phone was supposed to be delivered on the 6th of March and it was not received and when I called Vodacom, they said it was on a back order. Whilst I understand, it is a Vodacom issue, my issue is when you try to preorder the phone on Samsung SA site, it takes you to Vodacom and other dealers. Then they insist on the use of the Samsung Rewards app which didn't work when I tried to claim my free Gear VR with the Samsung Galaxy S7 Edge in 2016. When I called Vodacom today, they told me that since I had preordered the phone, I would still qualify for the headset, wireless charger and R500 voucher. When I called the Samsung call centre, they told me that I had to receive the phone by 15 March to qualify but when I protested, they told me that as long as I had an invoice for the phone for the preorder period, I would qualify. I'm sure that the invoice will reflect the date the phone is actually issued, which is likely to be after the 15th of March so what now????