Very very disappointed - upgrade

I am due for an upgrade. I am currently on a red flexi 570 line, I've been advised by Vodacom that I can't stay on the red flexi 570 line and get the new IPhone 13 Pro max, or any new top of the range Samsung for that matter. Being a customer for more than 18 years and Vodacom can't accommodate my request. Not an impossible request, I just need my contract the way it is with a better phone, isn't that the reason we upgrade. Very disappointed