After this incident, I have to say that Google webmaster tools still needs to improve a lot in terms of security level. The concept of having multiple verification files is not very safe for the webmasters.
Every website should have a single verification file. Multiple files can always lead to foul plays like this.
Moreover, i am very much surprised in the way Google reacted to the change of address request. This is what Google recommends for best results :
"For best results, follow these steps:
1. Set up the new site
2. Redirect all traffic from the old site
Use a 301 redirect to permanently redirect the pages on your old site to your new site. This tells users and search engines that your site has permanently moved. Ask webmasters to update their links to point to your new domain and make sure incoming links to your old site are redirected correctly using the 301 redirects.
3. Add your new site to Webmaster Tools
4. Tell us the URL of your new domain"
It clearly recommends that we need to first set a 301 redirect and then issue the change of address request. Obviously in my case, the 301 redirect was not set up as that guy did not have access to the server. He only logged in through a separate webmaster tools account and issued this change of address request.
It took 10 days from Google's end to wipe out all the keyword rankings for my home page and that also WITHOUT having implemented a 301 redirect from the server side. Isn't that absurd from Google's end. Ideally Google should have first checked out the redirect before acting upon the change of address request.
The change of address has a similar effect as that of a 301 redirect. I will elaborate it with this experience of mine.
Let's say www.example.COM is my site and www.example.NET is the other site.
The change of address request had been made from www.example.COM to www.example.NET. Now when i query Google for my web site name "example" I get www.example.NET as the first result.
Now when i query for my website url i.e. www.example.com, the number 1 result shows up the title and description of example.NET but shows the URL as www.example.com. On clickking this link i see my site www.example.com
This is exactly what should have happened on 301 redirecting www.exmaple.COM to www.example.NET.
I had withdrwan the change of address reuqest 2 days back and still i do not see any changes in the SERPs. May be Google will take a few days more.
Pls post you comments on this. I believe, webmaster tools needs some changes or else, things like these are likely to happen.