To be fair and use your analogy... your old car still continues to work as it did before.
We didn't just tune up the old car, we gave you a new one at 50% off the price based on your standing as a current car owner. The new car works on voice activation and costs a little more.
Your friends may want to continue driving your old car if they don't think the features in the new car warrant the price, which they can continue to do without issue.
...... thanks for you inspiring rather condescending commentary Ray. Now can you just take one step back and read what your customers have had to say just one more time. You might just perhaps learn something. Like tell it like it is - say it like it is in your sales pitch from the very start and stop being so *D a m d ed defensive - it doesn't help your case or your business because it has nothing to do with your tune up. It has everything to do with being upfront with your customer. So try learning from it if you're smart as it will pay in the long run. Fight it like you are doing and there will be a cost - trust me.