Just to let everyone know, I had a great experience with Hydor recently.
I emailed them awhile back when my Koralia Nano stopped working and I couldn't get it working even with the troubleshooting tips on their website. They replied and told me to send it in with a note explaining the problem. I was delighted today to receive a now working pump from their service center
This was particularly awesome customer service because this pump was from a used setup I bought, so I had no warranty or receipt, but they repaired it, no questions asked!