Below is my response to them .Hope you guys do same
Thank you very much for sending us mail , it shows your company have just woke up after 2 years .What makes me surprise that after you got-up you start asking about payment.
Can you please justify payment for what ? We have waited 2 years for you to complete the project and now with out starting construction you have requested for further payment ?
Payment for what ? which payment ? Show some humanity
Don t waste your time in sending me mail . I wont pay any thing till I see construction started .