Trouble overwriting files--help!

I can't seem to overwrite files...having trouble....I even just deleted my index.html file....and the site is still there? This is driving me crazy. My client's provider just went to this secure uploading, and I am not familiar with this program. I drag and drop....I also tell it to overwrite....I have been trying for days and hours thinking I am doing something wrong. Help please....I don't understand what is going on.
Thanks
Debbie

If you have succesfully uploaded the file (to the right place), then you should better ask the provider, why the change is not reflected on the site.