Denial of joining in central Govt job

Denial of joining in central Govt job due to non submittal of reliving letter from a overseas company. I got an appointment in a central Government organization and date of joining was 11/04/2017. Prior to joining I had to undergo pre medical examination. I attended the same on 19/1/2017 and owing to some concerns during the medical checkup I had to wait for some more time to get medical clearance. I cleared the medical examination on 05/04/2017 (Medical checkups are done by Organization Medical Officer). Due to non clearance of medical I did not submit my resignation and upon medical clearance I submitted resignation to current organization (In UAE) on 10/04/2017. The notice period of current organization was three month so I requested for extension of joining time up to June 25th. However Organization granted extension up to May 20 due to automatic lapse of appointment order after three months. I reported at the organization on 18/05/2017 with provisional reliving letter and requested HR to accept the provisional reliving letter and assured that original will be submitted upon all clearance from the working organization but they refused and deny the joining.