I have already a bad experience with this attack of unnatural backlinks, I used the link detox software to find out the harmful links, then list them and send emails to the webmasters. After some days I found that the links are not removed yet and there was no response from the webmaster as well, then I used google disavow tool. But still our ranking did not recover yet. At the same time we just change the design of our website and use 301 redirection. Not understanding what is the problem and what to do next?