upgrade *****

Good day

I did an upgrade on my number *** on the 6 March on the special where you get a tablet from Samsung. After almost 2 weeks I did not receive my phone so when I contacted the centre they said I must choose a different phone as the S23 plus is not available. I took a S23 ultra which they had to redo the contract now Samsung says I cant claim my tablet as we are to late. Please assist