I have never found that you need an enormous amount on knowledge to use (however I don’t use railgun!). I knew pretty much nothing when I started using CF but that’s a different question!
Unfortunately, as you probably gathered, the community will not be able to change your nameservers, so contacting support is the only way in this case. The community may be able to help you with the errors but if you want to transfer away, you will have to wait for support. I tagged @cs-cf and @cloonan and they may be able to have a quick look at the ticket for you.
I can say I have a decent knowledge in servers, domains and all these things, (Even I’m running a Discourse powered community like this on hetzner cloud).
I tried my level best to resolve my issue, I failed. SiteGround is providing Railgun, they are saying there is no issues on their side, CF is saying there is no issues here! Then who is the one making issues
Since SF has good chat support, and they guaranteed I decided to leave.
Anyways, I really appreciate your prompt response. I know the only way is to contact support, I thought someone from CF support will see and help me to resolve the requirement fast. That’s why I posted a topic here.