One easy fix from old school webmail days is to compose it in Word or similar and then copy paste when done.
I'm in the habit of always doing this if I'm writing a long message (but in notepad++ since it's way lighter than Word :p )
I just compose in the reply box but do Cmd-A, Cmd-C before submitting.
If you used Chrome or Firefox, you can get Lazarus: Form Recovery extension. Highly recommended.
Internet is my backyard...
Please read the Geekzone's FUG
This used to always happen to me when listing something on TradeMe.