Unfair billing

I have a new contract with Vodacom, only data/airtime no device no sim, I wanted to cancel it because of the 2GB_Bonus Data Bundle @ 25% Discount R 122.54 that keeps on occurring every month since January 2020 the last contract and i was promised that it is cancelled and it will never happen again now boom March invoice its there. And this 25% discount was introduced by vodacom in November (black Friday) 2019 which means their are busy forcing it on us without our knowledge. Why when i want to cancel the contract i am charged the data/airtime i have not received as yet. A - Subscription - Balance of Contract 1,956.60 293.49 2,250.09 Airtime Subscription – uChoose Flexi 125 (R108.70 per month x 24 months remaining) 2,608.80 391.32 3,000.12 Premature Cancellation Discount -652.20 -97.83 -

I feel that this is not fair because i have not used their airtime or data and i don't have their device or sim. Vodacom is taking advantage of us