Broken Engine mounts

Is it possible your local mechanic broke other mounts? Yes, it is possible if they did something wrong. It's also possible that something else was broken causing your vibration. Engine mounts don't usually cause vibrations but it's not impossible. It would help to answer better if you explain the vibration you're getting and when it happens if it's not all the time. Is it while the engine is idling or while you're driving. Is it vibrating all the time or only at a certain speed? Does it vibrate only when in gear? Describe the vibration. Is there any noise or clunking when you put the car in drive or reverse, or when you step on the gas from a dead stop? Any changes in engine performance since the mounts were replaced? What size engine is in the vehicle? Do you know what mounts were replaced and which ones your dealer said were bad? The answers to these questions will help to give you a better answer to your question.