We purchased 36 'Zero-footprint' PCs from 3C Technology last year having had a demonstration model for a few days previously. The PCs are great and the service offered from 3C is fantastic.
We had to return one of these not to long ago due to a faulty power board. Phoned up and arranged it within minutes, they didn't question our diagnosis in any way, or make us sit through a 'script' of questions.
A few days later the PC was returned fixed and has worked fine since.
This is how it should be done.