Horrible experience - Avis employé Finance Internship TUI Group

Horrible organization, I was left alone with 3 weeks experience as a trainee, taking care of important documents and payments, I felt many times that I had no help from my direct colleagues. Besides that, I feel that I did everything I could for them, did more then I was asked, worked extra hours to help colleagues, I only received 300 euros and even thought all my direct colleagues said they were very happy with my work, I got no response until today about staying. I did not even receive a no, I received a "I will contact you next week to tell you if we will be able to keep you". 3 months have passed and nothing.