Sold wrong contract

The very very poor service I am getting from Vodacom leaves me with no words. In March 2021 I was called and told that I am a very good and loyal customer I therefore deserve a discount on the contract I had for so many many years, instead of getting a discount a wrong contract which is costing far more than what I've been paying is loaded on my profile. I called since April to date nothing has been done amid being told that all will be rectified and I will get my refunds. Promises are never adhered to, changes are not made. I am very tired and disgusted of the poor service I am receiving from Vodacom. I want my refund and the contract be changed back to what it has been all along.