I have no idea which mosad you are referring to, but I can tell you that many, many yeshivas are struggling to pay their bills. I know personally of a yeshiva in which they are very behind on payroll and the "bigwig" who decides when and who to pay will not take a paycheck until all of the other staff has been paid.
I don't think you can fault a yeshiva for having no money (unless they are not being honest about having the $ to pay). Unfortunately, it is just a reality for many yeshivas. A person can decide not to work for a yeshiva in this situation, but I don't believe taking them to court will have any benefit. The school is not denying that it needs to pay. They just don't have the funds.