In this specific situation this is a huge problem because we ourselves have no way of linking a deposit to a Note, so unless we receive the Letter of Guarantee it's just a guessing game at best and we need to trust the user's word as we have nothing else to work with. We also have no way of verifying if the Note balance was partially or completely spent already because we do not know which one it is.
If you set a precedent by refunding this, and are expected to refund all future similar scenarios, then either you will go bankrupt or have to break that precedent when someone takes advantage of this and repeatedly claims to still own a funded note which they have actually already spent. Better to not set the precedent at all, I would have thought.
whirlwind.money has an FAQ page that actually can solves this problem. So I think whirlwind should just stick to the TOS they have and not take any responsibility for user errors. Even if whirlwind doesn't return the user's claimed funds, then I don't think whirlwind can be considered as stealing it from the user.
These two excerpts from the
faq page would really solve the problem of the user in question.
How can I send or receive Bitcoin instantly, anonymously and for free?
To send:
Go on the Dashboard page, enter your Note Private Key and select “Pay”.
Ask the receiver to send you his Note Public Address and use it to send him Bitcoin from your own Note balance.
To receive:
Send your own Note Public Address to the sender and wait for his transfer.
IMPORTANT!
Make sure you store your Note Private Key properly, support can't help if you lose it.
DO NOT share the Private Key with anyone, you will most likely lose your funds. To receive payments you only need to share the Note Public Address.
What is a Guarantee Letter and should I save it?
Whirlwind signs a Guarantee Letter for every action made on the platform, this includes deposits, withdrawals and transfers between Notes. We strongly recommend saving all Guarantee Letters, they are proof that an action really happened and can be used by you later on for different reasons ranging from Whirlwind support enquiries to compliance issues.