Google mapmaker seems to work pretty danged well these days as a method to fix local listings, edit and get correct information, and have it show correctly within google search.
Now, I've only been working on this "stuff" since about 2006....and its mostly been a frustrating "mess". There were periods when bad information showed up for a year or longer, regardless of how often and vigorously, and repeatedly one tried to get erroneous information fixed.
Mapmaker; google dot com/mapmaker works very well and very quickly these days in my experience. For me its a shock how quickly it is effecting accurate changes.
To use this one needs a gmail acct. Then search on mapmaker, click on the link. Place a business name, or address in the search box and see if google turns up "something" accurate, half way accurate etc.
If the info is showing but its wrong, go to the list of businesses on the left, click on the pencil stub link to edit, and a list of columns will come up that one can edit. Then line by line put in the correct info.
Now all this information is reviewed. My recent experiences are that the edits are done quickly. The one's I'm doing are being mostly approved within a day, and the changes go up and are seen in google within the next day. That is quick.
Its possible that for fast responses someone needs a "trust" level with past accurate edits for them to be approved quickly. For instance I started using mapmaker several years ago in its infancy and every one of my edits was rejected. (and I was giving accurate data). Then I stopped for over a year. Now its generating fast corrections on my efforts.
I had a restaurateur make some edits. It was his first effort. Corrections seem to be moving quickly.
Its also possible there is still spam in mapmaker. There was and might still be a period where "spamming editors" had infiltrated mapmaker.
The changes in mapmaker migrate to google search very quickly. In view of my past experiences I find that astounding.
Some background: After years of being a mess, in late 2011 Google made very large back end changes to improve google local (aka as google places, google + local, and now my business) (these googlers have an incredible identity problem). Following those changes the new "systems" limped along with many burps and problems. It seems though they have smoothed out and corrected many of the interim issues.
Now I am not a google lover...by any stretch...but in this area there has been tremendous progress.