Dang, always sucks when PSA damages a card. Sorry you are experiencing this! As others have said, PSA damaging cards is comparatively rare. Given the number of cards submitted though, hearing about it is common enough. Most of us here are large-volume submitters so we’ve had damaged cards here and there. Expecting larger figures in the community to get up in arms about something like this is not realistic–even though this is a really tough experience that we all empathize with.
PSA has damaged my cards twice, both times they admitted to the damage. The first time the card was damaged before grading, and they paid out the declared value of the card plus the grading fee. The second time the card was damaged in encapsulation, and they paid out the difference between the graded value and the damaged value, plus the grading fee.
It will be a tough process since PSA did not admit to the damage, but hopefully that gives you an idea of what kind of compensation you can expect.