I have a problem with my page's backlink profile.

I have a page for mobile app development, since mobile app keywords are very competitive we start to create backlinks for the page obviously most of them were unnatural links. We expected a backfire but increase of ranking of specific keywords we create backlink for kept us creating more and more backlink. We managed to increased the ranking of that keyword from 50 to 35 in almost 3 months. Google crawled almost 350 links we created. Everything was perfect until one day, my page just goes down from 35 to 70. We expected a backfire as I said earlier but the problem is now I think page is being marked by google or something, whenever we create a backlink regardless of its quality, page seems to stay at the same place, results around my page are moving up, down and the results are always changing. But no rank change for my page. Is there any way, I can retrieve this page it to its original condition atleast to a condition where backlinks will work. Please help me. Thanks in Advance