Recently I noted that my app ranking was going down after a major update .
rank has fallen from 100 to 172 in adventure game category
also, read – Why My App Ranking is Going Down
so I use this service to regain my lost ranking
https://app2top.org provide cheap Incentivized Installs at 0.1 per install
so I ran the App2top campaign for 10 $ and got 100 downloads and ranking was back its normal position