They don't refund such things and the best thing you can do is just don't stack high stamina numbers and spend it partially.
it's just bad design that you have to avoid, let it be intentional or not.
Because in some areas they are completely deaf to reason, though I think this button causes them many tickets.
And its really not so hard to make additional popup window with options like (raid100/raid1000/raidall) instead of this cursed button right there.
And their response is really brings nothing but even more iritation - it's just so lame and unprofessional.
"Yeah we know this button which pisses people off right there but PLEASE UNDERSTAND gl hf bb"