As a couple of people already mentioned, there's only one way to get tires mounted. Here are the detailed instructions:
- Remove wheels from car.
- Load wheels into car/truck.
- Drive car/truck to shop.
- Hand wheels to shop employee.
- Ask shop employee to be careful not to scratch rims.
- Depending on shop, point out to shop employee that tires are directional and/or asymmetrical.
- Get wheels back.
- Check that tires are mounted in proper direction.
- Check that wheels are not scratched.
- Load wheels into car/truck.
- Drive home.
- Mount wheels on car.
That applies to any car. I wouldn't dream of letting a random tire place work on my Elise. And even less leaving my car there unsupervised.
Sorry to hear that this happened. It hurts to see your nice car like this. But you were taking a big risk. I could tell you a few stories... and they include a Lotus dealership.