How do I change my 'user' name?

Hi
Just popped on to see reviews for qsl-tenders ltd, who are scammers. (Offer free trail, but in the T&C's actually just auto bill you for a years' subcription if you don't read their small print, which is how they make all their money!!!!) Anyhooo, off topic again lol, sitejabber, just 'gave' me a name and didn't ask me to apply one I wanted to use, so how can I change my name please? Been into profile, put in a nickname, which they pushed into the middle of the other name they gave me...oh for pete's sake...so, help a newbie please!!!
Cheers ev1 xoxoxo