Mission to Seafarers says the Supreme Court Judge in Delhi has referred the case back to the Magistrates Court to go to full trial again.
Last week the Indian Supreme Court told the men the case will be re-examined.
The men have been held for 625 days without trial since 18th October 2013, and it is thought their new trial may take up to six months to begin.
35 men are being held in total: six Britons, 12 Indians, 14 Estonians and three Ukrainians.
Twenty-one months ago the men, who work as anti-piracy support teams in international waters, were arrested after India alleged the men were in the country's waters in an armed vessel.
Mission for Seafarers has been supporting the men, who have been held on suspicion of terrorism offences, illegal bunkering (refuelling) and storing guns. The men deny all charges.
The charity is now making an appeal via the Foreign and Commonwealth Office (FCO) and the UK parliament, for urgent and immediate diplomatic interventions on this matter.
Paul Towers, one of the crew members in India, told Premier: "The families are utterly mentally and physically and financially at breaking point.
"We've seen family members pass away, God bless them, relationships have split up, houses have been repossessed."
"They may call for our re-arrest and detention, we may be able to get bail - like the men did last time when they were released - but at this stage we just don't know, so day-to-day now is just uncertainty."
Listen to Premier's Hannah Tooley speak to Paul Towers here: