it is impossible to fill a claim on trustpilot. 1xbit flags it as spam immediatly. They only accept good reviews loool those guys are incredible fucking scammers
I ran into the same issue sometime back when I tried to leave a negative review for them. It's ironic that Trustpilot is untrustworthy sometimes because of this crap.
This is why I decided to only focus on sites like Bitcointalk, Reddit etc where 1xbit cannot manipulate the sites however they want no matter how powerful they are. I suggest others to do the same in case you'll run into similar issues.