Refund of Modem & Security charges of Broad Band

I connected broad band service on my land line phone in April-2012 with combo plan-850 per month. In this plan modem was free, but BSNL charge Rs. 500 & Rs. 850 for security deposit in bill of May 2012. I disconnected broad band services on my Land line Telephone No. 0141-2503817 on 25th Nov.-2012, & deposited modem & all broad band accessories in BSNL Kartarpura Jaipur office on 26.11.2012, & got receipt. At that time JTO told me that your above said amount (500+850=1350/-) will reach soon on your address,. But after passing three months No any cheque sent to me. Please request to you for send cheque of above amount with 8% interest early as possible