Imagine you owe $15k to a hospital, and someone knocks on your door saying “hi, I’m from the hospital, can you pay us $5k?” You, in your naivety, head up to your mattress, get $5k in cash, then pay them. Turns out, they are not from the hospital. What happens if you say to the hospital, “unfortunately your identity was stolen, and now I only owe you the $10k left.” Given bank deposits are debts owed to you, this is exactly what the bank is doing to you.