Service Bond Related

I was worked with BSNL, (O/o TDM Bsnl Motihari which is under O/o CGM Bihar circle), from 24/12/2012 to 12/07/2016, I had applied for recruitment in central govt in 2015 and same intimation submitted to TDM Motihari. After the result coming out, I quire about NOC or permission letter and found that it has been not sent to circle office Bihar till. Later SDE admin sends it to the circle office with sorry for the delay and I got permission letter to appear in the exam. Then I request to central govt department regarding service bond transfer, and they accept my appeal as there is also a service bond for three years. They send a letter to Bihar circle for service bond transfer and the same I also send to Bihar circle with my request for service bond transfer as per DPE guidelines. After not getting a response I meet to GM admin who advises sending a resignation letter earlier. Then I send a resignation letter on 12/05/2016 effective from 12/07/2016 with requesting to service bond transfer, but not got any response