Recently there have appeared announcements on the internet: “I will help you to solve your problems for 13% of the amount!”
We inform you that only CRO (Control and Revision Office) deal with solving participants’ issues. CRO never charge any money for their work. The authors of such announcements are not CRO staff members and, accordingly, they are not able to solve your problems. What they do is simply inform us about your problem and we sort it out. (Moreover, so far all problems have been solved quickly enough.) Thus they do what you can easily do on your own, without any intermediaries and without paying any reward.
Please keep it in mind.