Does the manager's unwillingness to pay commission make the money earned questionable, or is what matters the original contract and his full consent, regardless of his later change of intention?

A hired person is of two types: a specific hire (ajīr khāṣṣ) and a common hire (ajīr mushtarak). A specific hire is contracted for a known period during which the hirer is entitled to all of their benefit. A common hire, however, is contracted for a specific task or for a period during which the hirer is not entitled to all of the hired person's benefit. Accordingly, if your contract with the two companies is for a specific task or for a period in which neither of them is entitled to all of your benefit, then you are a common hire, and you are entitled to the agreed-upon wage for the work. The hirer's satisfaction or dissatisfaction with paying the wage is irrelevant, as long as the agreement and contract have been concluded.