Your post was blank @SvetlanaD2982 and the subject line doesn't fully clarify the nature of your query.
What do you mean by "unblock"?
What are the symptoms of it being blocked?
What happened to cause the SIM to become blocked?
If you didn't buy a membership plan for 6+ months and it got deactivated that way then you'll need to contact 48 support to ask them if they can reactivate it.
If the problem is something else then you'll need to explain it more clearly if you want assistance from the Community Forum.
If you need to contact 48 support about this then see the links in my signature below.
