Datawind — Refund / Non receipt of Aakash Tab (UBISLATE 7+)

Hi,
I booked Akash Tab (UBISLATE 7+) in the month of February, 2012 and sent the four cheques (Cheque No.525888, 525889, 562554, 527908) of Rs. 2, 999 each (2, 999x4) to the 'Datawind Innovations Pvt Ltd' on February 29, 2012 via speed post no. EM[protected]JN, which was received at their end and released. However we have not received tablet till date (approx one year). considering the series of promises by Datawind team for delivery of Tab and inability to achieve any of them, we are left with no choice but to ask for refund of the cash paid, but we have neither received Tab or refund. can any body help us in this matter and guide us to take legal action.