[mothered]

2) I found the official invoice in .pdf from the website I purchased something else. I'm wondering if I can edit .pdfs with an editor that can do that, or that it will be better with Photoshop.

Go with whichever of the two tools/software you're proficient In using.

I don't know how they can figure out the .pdf was tempered with but it's my final option for now.

By viewing Its metadata.

Another thing, this sentence:

"Razer must positively identify that the Product falls within the applicable Limited Warranty period. We also need to verify that the Product was purchased from an authorized seller of Razer Products."

Makes me think that they only need to confirm it wasn't purchased from some weird ass shop which sells products but isn't authorized to do so.

What's concerning Is this:

We also need to verify that the Product was purchased from an authorized seller of Razer Products

They've stated It needs to be "verified", meaning to make sure It's true and correct, which may Involve cross-checking Its authenticity with the seller. I'm not saying It Is the case, but rather the possibility exists.

I'm glad they didn't say anything about the thrown away mouse.

That's exactly what I thought after reading their message.