If the deadlines they propose don't match your schedule, try other translation companies. The translation service market is highly competitive. To gain more clients, translation companies always give their best turnaround they can meet. Don't try to press the companies to speed it up to fit your schedule. Some companies might compromise, but that might result in a disaster later. If all proposed turnaround times don't match your expectation, your schedule might be unrealistic. Revise it for the sake of quality!