The AIFF after its meeting in New Delhi on June 10 had promised to send the minutes and the proposal for the new competition for further deliberation by the two clubs.
"We have not yet received any letter so far. I will ask him to send letter at the earliest as we are getting delayed in taking any decision," IFA secretary Utpal Ganguli said after a meeting with Mohun Bagan and East Bengal officials late in the evening.
But the Bengal governing body which is taking up the two team's cause at the parent body is still hopeful of a solution.
"Nothing is final yet. Further discussions can change things. Whether they will play the ISL or not I don't know but they can be part of a combined league," Ganguli said.
The IFA had sounded positive after their discussions with AIFF president Praful Patel on June 10 and said they were working on a new proposal.