Based on the sample descriptions, this does not clearly sound like a broken AF system. The most likely explanations are user setup or misunderstanding rather than shipping damage.

A few key points:

• The sample images reportedly do show areas in focus, just possibly not where the buyer expected.
• AF systems often lock onto the highest-contrast area, which may explain focus landing on a different part of the scene.
• A very wide aperture can make depth of field look extremely thin, making images seem misfocused.
• The viewfinder diopter may be set incorrectly; that affects what the photographer sees through the finder, though not the recorded image.

Useful checks for the buyer:

• Reset to a simple test setup in good daylight.
• Use one single AF point only.
• Aim that point at a clear, high-contrast target.
• Review the original files and EXIF.
• If possible, inspect the focus point used in Canon DPP.

Physical shipping damage severe enough to affect focus would usually require significant internal impact, often with other signs of damage. From the information given, operator error or mismatched expectations seems more likely than true AF failure.