Gov taken all my money

Hello, i was living/ working in Uk for past 5 years, and i went back to Lithuania in 2017 october. Ive found a job, i was working till august 2018 then i left since when i started to work i was promised 3 days of work and 3 days off pattern, and 700 euros after taxes. As time went by ive learned that there was over 20 people changed in my workplace over 6 months period... I had to work 5 days 12 hours a day and even more sometimes, i was hoping that the paywage would rise but in 7 months i only had 3 months when i was payed over 700 euros. So i left my job, joined jobcenter in Lithuania, since i didn't had 3 years exp in Lithuania working i don't get any benefit, they said look for a job and come by next month. Well i had some savings but then Lithuanian tax department showed up and took away all my money i had and left me in debt to bank for minus 610 euros... the reason was medical insurance that every lithuanian have to pay them and since i was working in UK i didnt knew that.. I did not get any warning letter or so, they just took all my money without offering a plan to pay it so i could still have some money to pay my rent, buy some food etc... So here i am, broke, hoping that world could help me out... Also i would really love to get some info is it legal that Lithuanian gov is doing to the people.