I'm currently stuck with a Lumia 800 with a penchant for crashing thanks to Vodafone's "repair" service.

I explained in a written letter how the phone would crash at frequent intervals (especially when playing or recording video). Being a developer I even wrote the letter as I would write a bug report with steps on how to replicate the problem and what not.

They returned the phone to me with a standard letter saying how they fixed the phone by upgraded the OS to the latest version.

The OS was of course already updated to the latest version before I even sent it to them. They even tried ringing me on the broken phone I had sent them so I could explain what my problem was. I'm not sure how they thought I would answer it exactly...

I tried again and received the same response. Needless to say, my phone is still broken.