German girl cheated with money what to do

I and a German girl was in a relationship for 3 years. I am an Indian by Nationality. The girl, Frau Kathrin Lehn belongs to Gruningen Village, City Riedlingen, State Baden Wurttemberg, Germany. Finally we broke up a month back, and she owed me around Euro 800 which she has taken from me on different accounts during the course of 3 years. Every time she has come to India, I have borne all the cost of food, travelling, hotels, etc. and she never had to pay a single cent here and I have never asked for the money as well. But on three different occasions she borrowed the money and promised to return them after a while which she never did. After we broke up I asked for this money to which she has not responded anything. In one of the mails she said she would repay the amount of concert tickets but unfortunately she haven't. I have sent her repeatedly mails but all in vain. I seek your advice on how to get the money back. As evidence I have few mails and whatsapp chats.