Four top executives of a delisted Canadian payment processor were charged Thursday in the U.S. in a 41 count-indictment alleging decades of mail fraud against the elderly and otherwise vulnerable victims.

The fraud allegations center on Vancouver-based PacNet Services Ltd., which stopped accepting payments after it was sanctioned by the U.S. in September 2016 as a transnational criminal organization (TCO). PacNet had operations in Canada, Ireland and the U.K., and subsidiaries or affiliates in 15 other countries, according to the Treasury Department designation statement.