I had a problem with my Lufthansa flights, in my opinion that was completely the airline's fault. At the desk during the day of flights, they (naturally) didn't give me any proper response, just a card with information on where to send complaints. I decided to pursue that, sent a refund request to the email address they had on the card. After to weeks of waiting without a single response apart from the automatically generated "we got your message, this is your issue number, we'll contact you as soon as possible", I decided to send another message to them using the complaint form on their website. I even included the issue number and mentioned that I had been waiting two weeks already. I got another similar automatically generated response right away, then nothing else for another three weeks.
What should I do now? I really don't feel like calling them, as that won't take me anywhere. Is there a place I can complain about an airline apart from suing them? Obviously I'm not looking for any costly ways of pursuing action, I just want to get my well-deserved response.
My situation is similar to this question, where the author was looking to get compensation because of messed up flights. I may or may not be eligible for a compensation, but not getting a response is simply not acceptable.