Only vaguely related, but… my GF had real problems with Amazon, trying to return a PS3 game bought in error (I already had it) to a ‘marketplace’ seller who turned out to be in Greece (unbeknownst to my GF).
Long story short the call centre folk were utterly useless, ballsed up the ‘claim’, then told us there was nothing they could do.
I emailed the MD of the UK business, who got in touch directly cc’ing their ‘executive assistance’ department or something, who resolved the problem virtually instantly, including refunding for the return postage (to them in the UK, they offered to return it to Greece). Was mightily impressed, but as with the OP, their initial procedures weren’t ideal.