If you had realized before April 15 that the bank had not characterized your February deposit the way you wanted them to, you might have had more options to correct the mistake.
As it is, if the instructions were clear and you didn't follow them correctly, I don't see how the bank can recharacterize the deposit for you. You would have to show that the bank made a mistake, or that their instructions were so unclear that you could not reasonably follow them.
