Is CloudFlare reliable or I miss something?

I run a simple VPS to host my wordpress blog, I signup for cloudflare free service. Never see much difference is site performance, but was still happy until early this month. I start getting all nginx connection limits to filled out, where as last month it has hardly <10 active connection, but not it has 1000 active connection. I found out on lsof that all connection been taken from IP: 141.101.104.127, which is one of CloudFlare IP. So, I delete my Cloudflare service account. But even after 24hrs of it, I still see those incoming connection. I report it to them, but all I get is to install mod_cloudflare to get actual IP involve in request. But hey my DNS is already on my server not cloudflare so why I still get connection through your channel. I finally end up blocking that ip frm my server and it seems to fixed the issue as it is more than 18hrs from last request from that ip. and it is more than 48hrs since I delete my cloudflare account. It seems I am missing something as my knowledge is not high in this regard. Is that my DNS is still not fully propogated? Though all online service I use says it is propogated (after all I use godaddy for dns).