Hello AnnaZdrogov,
Thank you for using Apple Support Communities.
We understand that you are having issues getting a student subscription to Apple Music. You confirm your student status, but are not getting a reply. Take a look at the following support article on getting a student subscription and verify that you are not missing any steps in the process.
Get an Apple Music student subscription - Apple Support
If you are still not able to get your student status confirmed, then you will want to contact UNiDAYS for help.
If you need help with your UNiDAYS account, contact UNiDAYS Support."
Best regards.