Ubislate 7+ not delivered (2 units) against advance payment

Hi, I had made a payment of 2 cheques of rs 99/- Each for 2 ubislate 7+ in the month of january 012. Booking ids: pmc320fe3ea2 and pmdda0698fe3 in the name of prabhu and ajitha. Cheque no. 4880 and 4881 (sbi). I am waiting for the last 6 months for the delivery, but no response from the datawind team. Every time I call up, they take up my address (as though they dont maintain any database) and tell me it will delivered in 10 days. This has been hepping since may and am still waiting for those "10 days". I am fed up with these people and would like to sort out this issue at the earliest. Regards, prabhu