1561. A creditor may not be compelled to accept anything other than what is due to him, even though the thing offered is of greater value.
Nor may he be compelled to accept partial payment of an obligation unless the obligation is disputed in part. In that case, if the debtor offers to pay the undisputed part, the creditor may not refuse to accept payment of it, but he preserves his right to claim the other part of the obligation.