Paid for Goethe Institut German Course, Received No Service or Support

I paid ₺8,000 for a German course at the Goethe Institut, but due to personal reasons involving my child, I requested to transfer to a future course before the current one began. I sent an email, but received no response. During the first week of the course, I visited the institute in person to explain the situation. They told me if there was space, they would assist, and that I would receive an email. Two days later, I received a rejection email. When I asked for alternative solutions, they never responded. I paid a significant amount and received no service in return. I will be filing a complaint with the Consumer Arbitration Committee. This kind of unfair practice needs to stop—what exactly did I pay for if I received no service?