Bad product

I bought a dual sim Hi sense E50 lite which is on an MTN network , I have a contract with Telkom so I chose this type of fone to use both networks but the second sim on and off data function doesn't work , why say it's a dual sim when in fact it isn't or there's a problem with the device since I bought it. I really need help here because money don't grow on trees and I had to sacrifice my hard earned cash for a faulty product