MBAir12 [Recovery] : Mac OS Sierra failed to download

Hello. My MacBook instantly stopped booting up, at first I've tried to recovery SSD from the recovery partition - it fails. (But I boot from the recovery partition from ssd, so it means it's ok!) After this failure I've tried to boot - it gets to the end and screen becomes black and MacBook restarts. Then I tried to recover OS X by the reinstalling from the recovery partition (people say that all files and programs will be ok) - It says "Mac OS Sierra failed to download" every time, as I understood, Apple removed last Sierra from the App Store. OK, APPLE, Next I found the same Mac OS Sierra 10.12.2 at the internet and tried to put it on the flash drive using the official apple instruction - after boot I've got strikethrough circle. OK, OK, I've tried to download Mac OS High Sierra from the App Store, but... it downloads the 18 mb version (or near) instead of full. OK,OK,OK, I've found it in the internet and with official instruction I've tried to write it on the flash drive. The same circle. OK,OK,OK,OK, I've tried to use the internet recovery partition, but it downloads Mac OS Lion (or something near, I didn't see, but the ui look was very old) recovery partition, so if I try to recovery Mac OS here, I'll loose my data. What should I do? I'm stuck.