[mothered]

Update: Replacement accepted! It was a process that went on for more than a month!
So they were insisting on getting a POP and a picture of the serial number. We went on for 6-7 emails with corrupted files, then I sent a POP made via receipt mansion but did not send any serial number, which I kept sending as a corrupted file.
In the end, it got accepted after I complained a bit about the process, but they still required a valid serial number, which they now requested also in text form: that's when I eventually sent the one I had, and today I finally got the email that said that my replacement had been accepted.

You handled It extremely well.

An SE to be proud of, congrats.

Thanks to @mothered  and @nephele for your support

You're most welcome, but you're the one who did all the hard work to ensure a successful outcome.