Super vcads for volvo

hi, am armin from bosnia and hercegovina.please help me.i have problem .i have super volvo vcads for volvo truck,bus,and construction equipment(dark-white,with 3 led.with hard disk and dongle ).obdauto.com is seller.i try conect volvo truck fm(2007 year),construction equipment (2007 year) but comunication dont work.chinese send me second interface but again not work.pablo ,i am electronic tehnician but i dont no what is the problem.connection stops at 10% of loading. Chinese suport is not good. What should i do. Can tell me is the diagnostics ok or should i send them back? In your opinion what is the best diagnostics for volvo trucks and construction equipment?