"None of that," says the Lord Marshall, quickly brushing aside your negotiation attempt with a wave of his hand. "I won't be shaken down by a gaggle of mercenaries for a few iron. The mendicants are yours just as soon as they return. In the meantime, you will make yourselves useful by fulfilling a contract with us. You each swore the Oath and I demand you honor it."

The pact allows for no compulsion of contract with a Free Company, only The Raven Spire can do that. However, if the Lord Marshall of Cistercia chooses to stand against you it will cause serious problems for your goals here. Not seeing a way out of this without endangering your purpose, you assent.