There were people mentioning that we should revert the balance to the moment before cancellation – and this would be the easiest and acceptable solution for everyone, however (unfortunately) this is not technically possible, we just don't have this possibility.

If he would just agree to make one more deposit (we actually never asked to deposit 5btc, anything above 0.01btc is eligible) we would've just add his amount as a bonus as a "consolation".