Hyderabad: Enforcement Directorate officials have collected hard disks and pen drives from the offices of Vihaan Direct Selling Pvt Ltd during their raids in Madhapur, Serilingampally and Swapnalok Complex, sources said on Friday. Sources said the multi-level marketing scam used blockchain technology and virtual currency was propagated or started by launching different websites, National Financial Fraud Victim Association secretary Gurupreet …