First I've heard about not being able to cash bonds. Have you posted a bug report about that?
Have you told the Zuma you can't sell them food because of the war declaration? I'm pretty sure that if you remind them of this, they will understand, and perhaps you can work out something else with them.
Not being able to cash bonds was because the city was stuck in an eternal holiday. I've committed a fix that I think corrects this problem.
