It really depends on what service that is not being performed correctly, if it is a service that is being contracted out like lawn service, or if it is a service provided by the management company directly such as providing monthy payments and reports. But your first step would be to review your property management agreement to verify the particular srevice is one they promised to provide. Second step would be to contact the broker or supervisor of that management company to try to resolve the issue directly. If that fails then you might want to consider using a better property management company such as Exact Property Management, 209-476-9000 or the brokers cell at 209-518-7136.
They are known for tayloring their services to fit each client.