Problem with ftp/login information

Hello,

My site was moved to another hosting firm a few months ago and worked fine till I tried to add some media. As I tried to add some media to my website in wordpress I’ve got a strage notification: “file could not be saved. Check if wordpress has the permission to save files.” So i checked the folder for uploads in wordpresses settings. The folder adress is other than the folders I have in my ftp form my hosting firm. So I tried to get help from my hosting provider, but they tell me it is not a problem of their settings. At my hosting firm there is a different admin login for cms (and I cannot login with that login because an error occurs) and the ftp files are different. So I assume that there is another ftp with the actual site files, a second wordpress account maby. But I cannot find the ftp of the working website by myself. Could anyone help me please or atleast tell me what to do next? I tried to use whoishostingthis, but the Nameservers are excatly the same as in my hosting settings. Please give me some advice what to do next. Thank you in advance.

The page I need help with: [log in to see the link]