Shocking service from Vodacom

I have a data only contract for 36 months with Vodacom. 1 year of my contract has expired, and I enquired on cancelling my contract prematurely. My contract is currently R600 a month. I have been given details of the value of my early cancelation and the value is higher than what it would cost me if I continued with my contract for the remainder of the term.

I have enquired with Vodacom, who cannot give me a reason for this, other than that the value is system generated.

As far as I am aware, the cancelation is 75% of the balance of the contract.

I also cannot understand why I should pay for data that they are no longer going to supply me with.

I am completely shocked that vodacom cancellations department are so unprofessional and cannot assist in the same way that they do when they are trying to sell a contract.