Horrible engineering work!

We are a struggling mechanical workshop. We trusted Cargo Crankshaft Rebuilders to do engineering on 5 heads/cranks we gave them. Rubbish work. Three of the jobs had to be redone. They told us they could repair a crankshaft on a BMW, charged us a fortune, it wasn't fixed, cost us R14,000 to redo the engine rebuild, then the crankshaft had to be replaced at a further R13,000 cost to our company after they told us to go "eff" ourselves. No accountability. We are now being sued by our customer and probably going out of business. We've lost over R30,000 on this job. Their work is terribly shoddy. Will never use them ever again. I don't think their workers give a sh*t about doing their work properly. Get paid, go home at the end of the day mentality.