updated the original post.
TLDR - they refunded 99% of my deposit, now I'm still waiting for the other 1% and for support staff to do something about it. I also sent an additional 10$ (minimum) to see if it was a problem with the wallet. That's gone missing too...
And now they have not replied to any of my messages in about 48hours.
Did you carry out all procedures as normal, or did you do something different that may have affected your deposit?
I really don't get why Coinbase would have an issue in an apparently straightforward deposit in this case, and it's absurd that they would take such a long time in order to even respond to your ticket, let alone taking 5 days to refund a very simple transaction and not even get the job right.
This just seems really unprofessional, that a group of so called "specialists" at Coinbase can't even competently calculate a refund.
Either way, I've quit using coinbase long ago since I realized the risks of hosted wallets and essentially entrusting your private key to an unknown third party. Besides, their support has been historically a disappointing aspect of their service, and they haven't made much progress towards that at all, it seems.