The shredder is most likely considered part of the technology department - which makes total sense because it would often be considered a computer accessory. (as in the way most stores that sell computer are sectioned.) It wouldn't fit in with the any other department.

If I were in this situation I would have simply stocked up on some things that I will need and use at some point - such as printer/photo paper or stuff like that to make the coupon valid. But thats just me.

A shredder may not be ADVANCED technology, but there is a circuit board inside and other mechanical parts. They do not run on pixie dust. There is still technology involved here. That being said, it makes your complaint seem silly.