Postponing /cancelling a meeting

hey guys

There was a letter sent around a week back for parents-teachers meeting . The subject matter of the letter is as folllws:

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Dear Parents/Guardians

A parents-teachers meeting will be held in xxx school on 28th November 2005(Monday) from 10:30 am to 12:30 pm. It would be in the best interest of your ward, if you attend the meeting.

The issue to be discussed in the meeting are as follws:

1. Attendance

2. Punctuality

3. Discipline

4. Academic Performance

With Regards,

Sincerely yours,

xxx

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Now the problem is that the meeting is to be cancelled as the date is just two days before the University examination, the teachers don't have time and some other problems. I don't know how to draft a letter for such sitiuation though i have tried. The following is the letter that i have written, please correct me or give tips for improving it.

Name

Post

xxx school

Ref No. November xx,2005

Sub : Cancellation of parents-teachers meeting (the sub dosen't sound right, please help me here)

Dear Parents/Guardians

The parents-teachers meeting that was to be held in xxx School on 28th of November 2005(Monday) is being cancelled due to excruciating (i don't know if it is an apt word to use here) circumstances. We regret for any inconvenience caused to you (Again this line just doesn't sound right)

The University examinations are likely to commence from the first week of December. We wish your ward best wishes for the examination.

With regards,

Sicerely yours,

xxx

I have to post this letter within 3-4 days time. It would be really kind of any one who could help me improve on the letter as soon as possible. Any help will be appreciated.