I bought an "open-box" HP LaserJet Pro M428fdn for almost 300 euro.
It arrives packaged only in bubble wrap, without any foam.
The duplex mechanism is completely broken.
I sent it back but now they want to keep my money for 15 days (3 weeks) before deciding what to do.
At least they responded promptly to my email.
Updated to 3 stars because they refunded me promptly after my complaints and offered to send me a new one.