Telegram is prepared for this, in fact they are practically set up for this. They have been a safe haven communication service for people in communist countries around the world. In fact Telegram is how the recent CCP list was originally leaked. Telegram also has optional p2p encrypted chats where not even Telegram themselves could access your messages. It's a great service and I strongly recommend it (our family has been using it for years just because it's a slick messaging app, never knew the day would come we need it for the other reasons...)