If your customer has a valid commercial Dr.Web license and at the moment of infection the system was protected with Dr.Web Security Space or Dr.Web Anti-virus (version 9+), or Dr.Web Enterprise Security Suite (version 6+), file a request for decryption at https://support.drweb-av.it/new/free_unlocker/?keyno=&for_decode=1.
Attach to your request the power of attorney that entitles you to represent the interests of the customer, as well as documents confirming that your customer is the legal owner of this license (a photo or a scanned copy of the license certificate, the payment receipt, an email from the online store or other confirming documents).