So, for making our contract breaking less bad looking to the Pangolins, we need to give reasons for it that are sensible and make it look like we're not intentionally being dishonorable. I mentioned some of these before (but they did not make it into the update) so to mention them again...
1. Jiraiya's death has cost Goketsu one of its three sealmasters. This has reduced the clan's ability to fulfill orders while also maintaining its own stockpile of seals.
2. Jiraiya's death has cost Goketsu a large chunk of its military power. This has necessitated adopting more members into the clan, all of whom must be kitted out with a sufficient number of seals, which exacerbates item 1.
3. Jiraiya's death and the deaths of a large number of Leaf's elites has caused a rise in demand from the Tower. Leaf is weakened, and requires more seals in order to protect itself from a war that is looking to be inevitable.
4. All of this has also revealed that the long term sustainability of this deal is impossible, as the death of the Goketsu could easily result in the Pangolins finding themselves to be suddenly without seals after conquering even more territory. If they think what's about to happen is bad, imagine how much worse it would be if they had kept up their conquest for another year and were suddenly cut off?
Further, we might offer some forms of compensation. Possibilities:
1. Goketsu will give up claims to the Pangolin Scroll, and will grant it to the Nara Clan (whom Keiko has married into) permanently. The Nara are famous for always keeping their word, so the Pangolins will be in good hands as far as future summoners are concerned. (Though we might also want to spin the marriage as a reason we can't keep the deal either - maybe the Nara will no longer allow it? Could be good to talk to Shikamaru about this.)
2. If Keiko and Akane are okay with it, maybe give the Pangolins the Elemental Mastery jutsu.
3. Obviously, the last month's delivery of seals will be free.
4. Perhaps some guarantee that we'll deliver some seals in the event that it looks like the Pangolins will end up conquered or destroyed in the next few years. Just enough to ensure they'll be saved, but not a consistent supply that they can use for conquest.