2002 Mercury Mountaineer

I had spark plugs placed in my truck due to the machanic advising that I needed a full tune up. After the sparkplugs were placed in the vehicle I was adv that the plugs were stripped and needed to be recoiled. Later that day I went back for the vehicle and engine light came on. The vehicle began to shake and I was advised to drive the vehicle a block later the vehicle seemed to be loosing power and hesitant to move. I called the machanic and was advised that it was fine. Later that night my vehilce would turn over but the engine knocked so hard that the knock sensors would not allow the car to run. What do you think the issue is. I know that the sparkplugs couldn't ruin the engine. I was adv that the truck has thrown a rod.