Payment In Full

What is the name of your state? Texas
I sent a payment to a hospital that was marked as "PAYMENT IN FULL" the amount was $788.00. They had sent an offer of acceptance of this amount, however the check arrived after their cut off date. They accepted the check anyway and deposited it in their account. They now claim that I owe them the additional $200.00 that was the non discounted amount. I sent the check with their offer and the current date. They accepted it and now claim that because I did not write the payment in full on the back of the check that they do not have to accept this as a full payment and just applied it to the account.
What are the statutes and decisions on the markings and terms of acceptance of checks. There was not a dispute on the amount due at the time the payment was sent.

[djohnson]

Contrary to popular beleif, writing payment in full on a check does not make a contract if it is cashed. They are under no obligation to accept your terms and can cash the check no matter the amount. They can just as easily write under dispute on your check and you not know it. Back in the old days when people actually got checks back it could be written on afterwards. Due to these things and others, your plan didn't work. They were and are withing their rights.