Dano:
https://vk.com/zabastovka_kna
should be:
group_id = 159183588
looks like id
you can see in the page code, but maybe there are more standard tools?
Answer 1, Authority 100%
For this there is a special method: https://vk.com/dev/utils.resolvescreenname
Send Zabastovka_KNA there, get the type of object and ID:
{
"Response": {
"Type": "Group",
"Object_ID": 159183588
}
}