no i am not using backlink from seo service...Did you buy any seo or backlink service?
Could be a negative SEO attack or you bought a low-grade blackhat service...
How to know it..It's mostly due to over-optimization of anchors
Thanks bro, i am try to waiting..Wait for 3-5 days, it will come back soon. - might be due to over optimization.
Always try to follow "Drip Feed".
Thanks for all....my site rank is come back...