Anyone who is or was an employee should submit a tax return for the year before because you can get back a lot of money from the tax. Even it could be much more than 1000 Euro. You should go to some income tax help organisation which you can find close to every neighbourhood in Berlin.
Just google the following: Your postcode and in addition the word Lohnsteuerhilfeverein and you can see the places close to you. Or even you should in Google maps. And really it´s not expensive there. Not at all.
https://liveworkgermany.com/2018/05/-tax-return-necessary-mandatory-worth-the-effort/
https://www.settle-in-berlin.com/tax-return-germany-steuererklaerung–for-foreigners/
