The International Organization for Migration (IOM) has set up information and support hotlines for persons fleeing Ukraine in different countries. Below are currently operational hotlines, and regular updates are here.
 
IOM Information Websites and Hotlines:

• Ukraine: 527 (free from mobile phones), 0800505501 (free from landline phones); as well as 527 website. 
• Poland: +48 22 490 20 44
• Romania: Online support platform dopomoha.ro 
• Lithuania: +370 525 14352 is run by IOM's Migration Information Centre, also available through live chat on this website.
• Slovakia: From abroad 00421 5263 0023, locally 0850 211 478; Telegram/Signal: 00421 908 767 853 (voice only); Web: https://www.mic.iom.sk/en/.
• Moldova: Bureau of Migration and Asylum (BMA): 080001527 (free from Moldova) and +37322820007 (from abroad); La Strada Anti-trafficking and Safe Migration: 080077777 (free from Moldova) and +37322233309 (from abroad).
• Czechia: +420 800 050 749; Email: infocze@iom.int; Website: https://czechia.iom.int/infoline

If you have fled Ukraine, are now in Vienna/Austria, and need support, here is some information that might be helpful:

Ukraine support hotlines in Vienna:

• Caritas Ukraine Hotline: 05/17 76 380
• BBU (Federal Agency for Reception and Support Services) Hotline: +43 1 2676 870 9460
• Diakonie Counselling Centre: +43 1 343 91 91

The following websites/info sheets also contain relevant information:

• UNHCR Austria 
• Austrian Ministry of the Interior: FAQs in German and Ukrainian 
• Federal Criminal Police Office: Human Trafficking Hotline (24/7): +43-677-61343434
• Info sheet by IOM Austria: Indicators for Human Trafficking in the context of arrivals from Ukraine (in German)
• Info sheet by IOM Austria: Prevention of Human Trafficking in private accommodation (in German)
• Information leaflet by NGO LEFÖ about dangers of exploitation and trafficking for displaced persons (English, Ukrainian)

Some more information for Vienna:

• City of Vienna's Arrival Centre
  Address: Schloßberggasse 8, 1130 Wien
  Opening hours: Around the clock, seven days a week  

• Caritas Day Centre Erste Campus main train station 
  Address: Arsenalstraße 8, 1100 Vienna

More information on the IOM Ukraine Response is available here.