MTN - Unable to upgrade on promotional price

I visited, MTN Canel walk, 2 months ago for an upgrade when they had told me that due to the new system they were unable to process the upgrade and was told I had to wait about a week. During that same visit I had signed papers reserving the IPhone XR and all other paper necessary. told that it just had to be processed on the new system but their system was giving trouble so I could not receive it on the day. 2 Weeks later the problem on the system was still unsolved and lockdown had just started. I had emailed the manager, Riaaz Davids, who had eventually gotten the upgrade processed (He was extremely helpful). However when going to the MTN store during stage 4, lockdown they had told me although It had been processed I could no longer receive the phone on the promotional price it was at the time I signed the papers. This is an outrage really because upon purchasing I could not get the phone because of their system not working. This was 2 weeks prior lock down so that can not be a factor in this. I would like the promotional price I signed for. Thank you