Never take your devices to them

We booked our cellphone S7 Edge in with them a month ago already to get a small cracked screen replaced. At first they phoned to say they don't have the same colour screen, then when we insisted to wait for them to "order" the same colour as a screen replacements include the body of the phone with a screen, they still tried to convince us to take another colour. After a week we got the phone with lots of glue coming out of the phone and the screen separating from the phone and still the old body with extra dents in it. We took it back, then when they gave it back to us, none of the parts belonged to the phone anymore and all the parts were so damaged that it looked like a 10year old phone. We took it back again, then we got it even more damaged and the glue now went into all holes, the phone doesn't charge anymore and apparently they cant find our original parts. What can we do as we already paid them a lot of money for the work and got 3 other damage reports from Samsung to state which parts are not original anymore. R3500 later, still no phone