The letter was issued by Sports Minister Richard Caborn in March this year following dialogue with the Independent Manchester United Supporters Association, who were expressing their concerns at Glazer's £790million buy-out.
IMUSA are increasingly concerned at the direction of the club, especially now directors Nick Humby and Andy Anson have tendered their resignations, which will take effect from February.
"We are astonished that a written request, that was then followed up with a telephone reminder, made by the Minister for Sport in Tony Blair's government to the owners of a Premier League football club for them to meet with representatives of the fans of their team, has not even been given the courtesy of a reply," said an IMUSA statement.
"Given the amount of time that now elapsed since this request was made, it now seems unlikely one ever will be."
IMUSA accept that Glazer, who suffered two strokes earlier this year, may not be well enough to make the trans-Atlantic trip.
However, they note business at Old Trafford appears to be continuing as normal, with a family spokesman last week suggesting United were in a robust financial shape, and cannot see why at least one member of the Glazer household could not make time in their schedule merely to answer the letter.
"If the family spokesman is to be believed, the business is thriving," continued the statement.
"We therefore do not understand, given the gravity of a written request from a Minister of State, why no other member of the Glazer family has assumed responsibility for responding to Mr Caborn's letter.
"IMUSA does not believe the Glazer family has a serious interest in commu