At the moment US embassy in Poland bid asking to wait till ur fiancé will receive instructions from the embassy to schedule the interview for ur K1 Visa.
Sadly waiting for that letter via post office might take long time. So what do you do?
You should wright an email to the US embassy in Poland to this emails:
The following text, adding ur info:
Hi! I currently can not get any mail delivered to my physical/mailing address.
Can I please get my instructions for the K1 visa as an email instead?
Case #:
Passport:
Name:
Date of birth:
Thank you very much and have a great day!