Browser does not show my website

Please help. My website www.onestudy.co.uk was working fine today until I uploaded a new index.html page to SmartFTP today and also bought a licence. The new page is not showing in any browser. I just get the Perfect Hosting Web Page.
Do I need to do anything or is this just a time thing where I have to wait 24 hours?

Thanks for any any assistance.

I had uploaded the Index file with a capital I and it did not accept it.
Once I changed it the site was fine.
Thanks for your swift response.