Bad customer service

On the 11th of August 2015 I phoned the call center to request an invoice for a flight I took a couple of weeks prior. The lady informed that that they cannot assist me and that I needed to email my request, they gave me the email address and I emailed. I received no response, two days later I emailed again. Still no response. I phoned the call center back and I was told that they can't really help me, I also cannot contact the accounts department as they do not have direct numbers (seriously??) and that it takes seven days. NONE OF THIS IS ON THEIR WEBSITE! The call center agent then realised that they gave me the incorrect email, she gave me the correct email address and then put me on hold to see whether they have received the email (but I can't contact them directly?) They haven't - they will email me and there is nothing more that they can do for me. I demanded that the problem be sorted out - the call center agent then placed me on hold until I put down the phone. This is extremely unprofessional and I need an explanation as to why the agents are so unprofessional and why a simple tax invoice cannot be emailed to me.