Homepage keeps disappearing and reappearing for important keywords every few days

[GemmaApril]

My homepage keeps disappearing from the SERPS for my most important keywords. My home page has been in number 2 position for years. When the home page disappears it will not even show in a Google search for my business name although it is still indexed. When the home page is not showing an internal page shows instead but in position 6. When the home page is back the internal page does not show. There are no issues being reported in Google Webmaster. When I realise that it's down I do a fetch as Google and request reindexing. No idea if this is bringing it back or not? We are so worried about this and totally at a loss. As are the three SEO companies I've called. Would really appreciate it if someone could give some advice.

NSFW https://goo.gl/dwA8YB

[EGOL]

Try copy/pasting a couple random sentences from your content between quotes in a Google search.  This will show if someone has grabbed your content and has a verbatim duplicate indexed.  If another site with reasonable power has grabbed your content, they can displace you in the SERPs.   Also, do a screen capture of the SERPs when your site is present, and another when your site is missing.  If a different site is on the first page of the SERPs, check it out to see if they have grabbed some of your content and pasted it on the page that replaces yours.

[GemmaApril]

Thanks for the reply. I tried what you said and I found two people in our network were directly using the text from our home page on their fb business page. Not sure if this makes any difference but asked then to change. Also found a directory that we hadn't requested list our business with the exact same home page text. I've asked for that to be taken down. We have literally tried everything we know how. And even the SEO company we are using doesn't seem to know what else to try. Our website home page will not even appear when searching for the business name.

[EGOL]

Its possible that you have a single-page penalty, though those are rare.

For another site with duplicate content to displace a page of your site from the SERPs, it usually has to be about the same strength as your site or superior to your site.

Some of our pages will swap in and out of the SERPs when the same content is on other websites of similar strength.   If we can't get the content removed by contacting them, and their use of the content is infringment, a DMCA complaint to google will usually fix the problem within a few days.

[GemmaApril]

It definitely does look like we have a penalty as the home pge appears for the keyword on page 8 whereas if used to be in number 2 position. Ive had a look again at back links and one seems particularly dodgy from a few weeks back. In fact the site has now been removed but unbeknownst to us had a link to our website. Other than that I am stumped. Would you recommend re-writing the home page content or could that do more damage than good.

[EGOL]

If your site has a penalty, fixing it will require determining why the penalty was given.

Most likely it has something to do with breaking the webmaster guidelines.  That is best assessed by the webmaster himself, and if the webmaster can't do it then an expert at identifying Google penalties is the best bet.  People who are not experts at penalty identification will be guessing and you don't want to guess, do the recommended work, wait to see if the site recovers, then see no recovery, guess again,work, wait, find nothing happens, etc.