Unlock zong mbb device?

Hi, how can I unlock my zong mbb device so it can run other sims ?
And second thing is, can I use regular sim in mbb device after unlock ??

Which specific device?

When I bought a device I was told it was hard locked to the specific Zong SIM card which it comes with and cannot be unlocked even for another Zong SIM or changed from prepaid to post paid.