Haven – “Do not tempt the desperate” [Campaign 3, Mission 3]

I'm playing on normal difficulty. The mission is easy. I'm completing it without any major problems. In the first few weeks, Kalindra's raids were annoying, but then they stopped. Now, I don't have enough gold to buy upgrades. I earn about 140k per week + I exchange resources for money. This is enough to buy everyone except the Guardians. I've already accumulated a legion.