So I mistakenly wrote a check with one amount in the number field ($100) and one amount in the written field ($1,000)to a company an a balance owed. I meant it to be $100 but I understand the legal field is the written field so they deposited $1,000. I had my bank reverse $900 but it was reversed back 2 days later. I contacted the company and they informed me they can legally deposit the written amount on the check even if its much more than what I mean to send and that their "hands are tied" and that basically too bad theres nothing I can do about it. My question is do I have a recourse at all? Can I REALLY do nothing simply because I made an obvious mistake? What if I had written a million dollars? Ten thousand dollars? Would they have tried to deposit it and sued me when it bounced? Is there anything I can do?

The company you sent the check to owes you the difference. If you in fact owed them $1,000 and was making only a $100 payment, your mistake is your responsibility. Your bank can't pay it for less because you now ask them to. The company can't deposit it for less. The check amount is what you wrote it for.

And yes, the written text is used over the numeric amount.

My dad wrote a check improperly also, however his situation seems to be less "cut and dry".... Please offer your thoughts.

April 2010, he paid his federal taxes with his personal check. He owed $404.00 and wrote $4004.00 in the number portion, but wrote out four hundred four dollars in the written portion.
The bank processed the check for $4004.00 and made his account overdrawn.
The bank then "put" $3600.00 into his account to prevent the overdrafts.
In May 2010, IRS (US Treasury Dept) sent him a refund check for $3600.00. The bank told him to sign it over to them as they had given him a "mini-loan" to cover the costs back in April.

This part is still unclear to me, but the local bank says that they sent the check to their "parent" bank- CoMerica, who was suppose to credit the treasury department with the $3600.00, however the treasury department states that they have not received the money and that my dad is still responsible for the $3600.00

I am trying to get clarity on how much money was actually paid by the bank to the IRS. It does not make sense why each entity feels that they both are "due" this $3600.00 dollars.

IRS has told my dad that he is responsible for the $3600.00 and that they will withhold his future income tax returns until the amount is paid back.

Since this can get much "uglier", my questions are:

1- what is the possible liability the bank holds for cashing the check for the numerical value as opposed to the written value?

2- Where can I get documentation to substantiate this issue?