If you received this and signed the check in AL? Then AL law applies.
If so or If not please give me the points of law as to why or why not
Here is a link to the code section that covers this.
What you are describing is called "accord and satisfaction"...and if you look at section c of the law it provides
a claim is not discharged under subsection (b) if either of the following applies:
(1) The claimant, if an organization, proves that (i) within a reasonable time before the tender, the claimant sent a conspicuous statement to the person against whom the claim is asserted that communications concerning disputed debts, including an instrument tendered as full satisfaction of a debt, are to be sent to a designated person, office, or place, and (ii) the instrument or accompanying communication was not received by that designated person, office, or place.
I bet if you review the paperwork you received from them, someplace it states
"communications concerning disputed debts, including an instrument tendered as full satisfaction of a debt, are to be sent to a designated person, office, or place,"
If so? you have to send the check to that person/office/place or it is not valid.
Please let me know if you have more questions. I am happy to help if I can. Otherwise, please rate the answer so I may get credit for my work.