There are two ways of dealing with negative comments that are put up about your company: the first is sending them a very rude, hot-headed message about taking that message down and threatening legal action. This will probably not take you any where. In a lot of cases, the people who run the site actually do not even know of the presence of the negative comments, venting at them is a bit pointless.
The second method is what we recommend and practice ourselves. It is a three step process that involves the right amount of politeness and force that will get the message across without provoking a negative feeling from the other party.
Step 1: Send them a polite message informing them of the negative comment and explaining the situation and asking them to remove it. Most often this usually does the trick.
Step 2: In case Step 1 fails, write to them again, politely, with pretty much the same lines, adding, again politely, that if they didn’t, you would have to think about the legal course of action. At this point, most issues get resolved.
Step 3: The final step is telling them about the legal action that you could take if the comment is not removed. Here too, it is important to remember that being polite will accomplish a lot more even at this late a stage.
When dealing with negative comments, remember that getting angry and yelling and venting is less likely to go anywhere in comparison to an civil conversation about the same. In fact, throw in a bit of flattery in the first two steps, it will certainly go far!