All you need to do is keep your wallet in your pocketThat's a nice sentiment, but it's only part of the picture. If you do that, then the company doesn't even know that you were a potential customer, so nothing has been lost to them from their perspective.
The best approach is to keep your wallet in your pocket or buy from a competitor, and then contact a human at the company that you didn't buy from and give them a detailed explanation why you chose their competitor instead. This way you actually get attention, because from their perspective the sale came straight out of their pocket into a competitor's. If they won't listen to that sort of reasoning, they're going to sink anyway.