R we eligible for weekly off

Sir , I am working a army establishedment as a civilian employee under MoD. here we work in shifts duty, 7 days in a week. AS afternoon shift: 1300-1900, morning shift: 0800-1300, night shift:1900-0800 again it repeats likewise in pattern. here we are performing daily duties and don't have any weekly off. As per my knowledge ,according to rules everyone's must have a weekly off in a week or 1 rest day (means period of 24 hours starting from midnight). Is this true. give me a suggestion.if they r doing wrong.