Poor service

Some background, my vehicle was serviced by them at the beginning of the year, but the vehicle did not run correctly. The vehicle had a shake when accelerating. In March, the vehicle started overheating due to a faulty fan. The vehicle was taken to Lance's auto shop to fix the problem. Firstly, they corrected the problem in a manner that the fans are permanently on. Secondly, they told my husband that the shakes are caused by something in the engine, and they have to redo the engine for R25000 (this is more than what the vehicle is worth). I ended up taking the vehicle to someone else for a second opinion. The second opinion I took it to said that there is nothing wrong with the engine, but they will see why the vehicle shakes. Initially, the second opinion people did not look at the spark plug because they were supposed to have been replaced during the service at the beginning of the year. The cause of the shakes while accelerating was oil on one of the spark plugs, caused by an oil leak. The second opinion people also replaced the fans relay, which Lance's auto shop said they replaced but clearly did not. Now the vehicle ran correctly, and I did not have to redo the engine. Thus the complaint is, Lance's auto shop charged me for replacement parts that were not replaced, they charged me fully for repairs that weren't done, and they are clearly not knowledgeable on the working of a vehicle if they cannot even identify a fault with a spark plug.