Vodacom sucks you dry

I am absolutely sick and tired of Vodacom and their non existent customer service! For months I have been querying why my bill is so high, I keep getting promised the added data charges will be removed and refunded for what has already been paid and yet every month the same thing. Now I want to cancel my contract (because I'm going overseas not even due to their shocking service) and I get told I have to pay R8130 to get out of the contract! I have a Samsung S8, on a Smart S contract..surely I should only be paying the balance of the phone value and not of the entire contract plan?! 25% 'discount ' but this is ****************! I have been a loyal vodacom customer for years but never again!