Hello.   Anyone can write a "warning"  with a headline that "such and such" is a scam;   such warnings have been made about Bitcoin itself, and there are many 'suspicious' actors or 'businesses' that might or might not be schemes to cheat people out of their bitcoins or money.

Do you think you could provide an explanation of what you are basing this on?

What is XCFD.COM doing, in what way are they cheating or being dishonest, and.... how do you know  for a fact they are perpetrating a "scam" ?