Quoting from [Rubert Fang]:
The time taken can be anything from 2 months to 2 years....... Many factors can make changes in the timetable.. especially financing..... It is possible they had to chnage finacing or something else happened to put back construction....... Just don't build anything until he is ready and keep his order in your "pending" file to be ready to make when he gives you the first payment.