ANGRY!!!! with the JP MR ALEX TAN YAN BOON

So Angry, we had on 1 June 2013 contacted JP Mr ALex Tan Yan Boon to be our solemniser  on 7 Dec 2013. Zen contacted him via email and his reply came quickly on the morning of 2 June. From the timing that we have requested, he knew that our solemnisation is gg to be after the 1st march in. He also replied that he was free on the day. After which he contacted Zen via sms and advise us to change to 8pm instead. we told him it is ok.. we are ok with his suggested timing and wanted him to sign our consent form soon. He told us that

The consent form has to be signed in original which I need to meet up with both of you in Aug if possible. (3 months before yr actual date).  

I will reserve the slot for you.

on 2 Aug, I told zen to email MR tan to fix a date for appt to sign the consent form... N GUESS what??? 3 Aug which is today, Zen received his email...with

I just received an assignment yesterday and may not be able to solemnise for you on 8/Dec.

Can I get another solemniser for u?

Feel that he is so irresponsible! Imagine we only contact him at a later date? now is like 4 mths in advance.. imagine we only contacted him 3 mths in advance to find out that he wont be available for us?????????
now that im writing this post.. I ve asked Zen to forward me his email... Im thinking how to reply to him... SO VERY ANGRY NOW