Hello Nikita Dmitrieff,
Thanks for your question.
I would be assisting you with the mutiple issues above. Mainly with phone verification.
For the first issue, If possible, try using a different phone number. We have seen multiple issues with sign up on different posts here.
As an alternative, try signing up using your phone. I have seen this resolve this issue for others.
If that doesn't help you can reach out to billing support. Billing support is completely free, but since you don't have a subscription yet you can dial the global service numbers here:
This also applies to Pay as you go.
For the school credit issue, Ensure that you are using the correct email addresses (both personal and school) and that they are properly linked to your OpenAI account. You should try signing in with a private browser.
You can mark it 'Accept Answer' and 'Upvote' if this helped you
Regards,
Abiola