Helderberg propshaft centre POOR SERVICE

I took my navara for propshaft inspection. They removed it and showed me the centre bearing and rear uni joint was damaged. I had it replaced. I was under the impression the prop was getting balanced. I paid R2460. Prop was refitted and i left. The bakkie vibrated immensely and i sent them an email i am not happy. They said i must bring it back, i came there after 1 day and they told me they didn't balance the prop, they will balance it now, they removed it and balanced and refitted it. They said its ok so i wanted to pull out the shop, they closed the gates, I'm not leaving without paying and they charged me another R575 to remove n refit prop plus balance. But they were at fault and they caused me to drive up and down and they know they should've balanced the prop in the first place.