Work not done as specified

2 months ago I had my radiator replaced by Silverton Radiotors Stellenbosch, they assured me the water pipes had been checked and flushed, yesterday 1 of the pipes from the radiotor to the engine burst due to blockage and this caused the car to overheat and blow my top gasket. Luckily I noticed that the the cars performance was changing and pulled over and towed the car home. I now have to pay to have everything fixed at my costs as everyone is passing the buck and when I got threw to the franchise manager the call died and I can't reach him anymore.