Contracts like this, spawned from a map are very hard usually. They do actually have pretty good loot though. I can imagine there would be 5k-10k crowns to be had there depending on how fast you can mow them down and sell their weapons. Also I feel these locations often have uniques. In your case, I would cancel and come back when my company hit lv11 and you got at least 2 heavy troopers (wielding 2-handed weapons).
To be honest, this is probably a mid-tier enemy. But they can still really wreck you at lv7. High tier undead locations is all of that and on top a few vampires and lost souls.
To obliterate this specific enemy composition I would want to have at least 2 archers with 80+ ranged skill to take out the necromancers in rounds 2-5, at the very least 2 soldiers with 200+ armor and greatswords or warbrands to kill the bulk of the skeletons in rounds 1-5 with AOE attacks (they absolutely need reach advantage and 30+ melee def. otherwise they will get killed very fast). The enemy damage comes from skeleton guards who wield 2handed weapons like polearms, greatswords, greataxes. You can use archers to whittle down their armor – usually after you killed the necromancers. Engage those with shieldbearers (at least 150 armor), if possible burst them down in one round before they can attack you.
All of this requires at least 12 people, archers and heavies lv6+.
The very first round you must charge the enemy and not wait until they reach you. Archers (in the 2nd row) need to advance 1 tile to hit the necromancers with their aimed shot, 2 for a quick shot.
Careful if you engage their archers in melee combat, since they wield daggers and can possibly kill your heavy armored guys if they dont have good melee defense and attack.
Skeletons are highly resistant to arrows (hp dmg) and, i believe spears also. My shieldbros would usually wear swords or warhammers at this stage.
12 experienced soldiers would absolutely crush this army. I suggest you come back later and go on a rampage :)