I can attest to never seeing the cylinder piece before.

I'm not going to even comment on the paraphrased dialogue that is above. That is not at all how it went, and I can understand the OP is trying to make himself sound right.

The pads were not used. I'm the only one that works in the company, thus the only person touching the boxes. I explained the Rotex does not use the black and gold boxes for their pads anymore. I explained I put the rears in the front box and shipped in one package. I offered a refund.

I got a little defensive when I'm accused of ripping a customer off by selling them used parts, and then have them challenge that I'm the only one touching the boxes by saying they found an extra piece in the box. I wish he would've said that in the first part of the conversation and not after goading me about how I'm not the only person touching the box at our shop. After several "I am the only person" then the extra piece was mentioned.

Please send them back.

I'm sure there are 100's of customers that can attest to my customer service and quality of parts delivered.

And yes you got me on a bad day, not an excuse just throwing it out there.