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When Travis Hartinger found his dream home in Chicago, only one thing was missing.

"We needed to update the kitchen," said Hartinger, who works in apartment sales and lives with his wife.

So he saved up for the $45,000 fix, took out a loan and called in a contractor. Hartinger told ABC News he liked almost all of the work that was done - except the time frame.

"I was really happy with the finished product," he said. "I just thought they took too long to complete it."

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And that's why Hartinger - like many other Americans have - went online and wrote a review of the company.

"At the end, we are 95% happy with how everything turned out but we were told that this would be a 3-4 month project and by the time everything was signed off it was closer to 6-7 months. I would never refer them to anyone," he wrote.

To his surprise, after he posted the review on a consumer rating website, he was slapped with a legal letter. In it, the contractor accused him of making "false comments" and said it was pulling the plug on his 10-year warranty.

Experts say it's a growing issue: business owners retaliating after customers post critical comments on everything from handymen to dentists.

"These lawsuits are a form of bullying," said Evan Mascagni, the policy director of the Public Participation Project. "They're a tactic to silence your critics and force them into submission to pull down their negative review."

But some small business owners said that they rely on word of mouth and that sometimes a negative comment was unfair and devastating.

Consumer advocates said there's no way to guarantee that you won't be sued but they suggested keeping these guidelines in mind when posting a review online:

1. Stick to opinions: Use words like "I think" and "in my experience."

2. Get evidence: If there's proof - i.e. a hair in your food or a discrepancy on your bill - snap some pictures for backup.

3. Read the fine print: Before signing any contracts with a business, make sure there's no clause forbidding you from voicing your opinions online.

The third tip is a mistake Hartinger said he'd never make again.

"I had no idea signing this contract meant signing away my right to [an] honest review," he said.

The good news for Hartinger: After a request for comment from ABC News, the Chicago company said it would reinstate Hartinger's 10-year warranty.

ABC News' Rebecca Jarvis and Michael Koenigs contributed to this story.