I often find that spells to resolve situations and bring then to a good conclusion are empowered by the waning moon. For me it represents the power and choice to improve what you already have over the desire to obtain what you don't. If you want to meet a nice date use the waxing or full moon. If you want to end an argument with a partner use the waning moon. Does that example help?
Correspondences are optional in magic anyway. They help but are not required
Banishings, habit breaking, weight loss, break up, stop gossip. Basically if you're sending something away from you the waning moon is the better choice. Curses might work better, I don't know. Protection might also be good since you're wanting to keep negativity away, but you can do a protection when its needed, not a particular moon phase unless you wish to do so monthly. [I tend to do a monthly protection on the full moon] the push and pull of the moon can help our spells, but if its an emergency, its best to cast regardless of the moon, the desperation can add a lot of energy to a spell.