Speaking from experience, many traders are not yet familiar with the concept of KYC (Know Your Customer/Client). Under Tradenix terms of service, you can read:
Supelo Invest S.R.O. is conducting an extensive KYC upon the opening of account and on an ongoing basis.
The documents that you are required to submit are as follows:
ID proof: any one of the following
Any government issued identity card (such as driving license).
Address proof (2 documents from the following categories):
Utility bills provided that they are no older than 6 months;
Bank/Telephone/credit card statements
The documents should be sent from the registered e-mail address.
The KYC documents needs to be self-attested by you. "
Please take this part seriously. For any of your traders, you also need to be similarly strict.