I have never had trouble with a cel dealer... but 
I just recently had some trouble with a private 
collector.

She is "Getting out of cel collecting" and is 
trying to off a bunch of cels at once.  After she 
made a deal with me to make payments (and set no 
deadlines) she writes me to tell me she is 
cancelling my order.  Whatever... To me, this 
translates as "I found someone to pay the full 
price up front so you are out of luck no matter 
what our deal was".

No warning, nothing... just "Order Cancelled".  Oh 
well... I am sure a cel dealer at one of the cons 
I am going to will have the same characters at 
half the price she was asking.  I just made sure 
all my friends were aware of how she dealt with 
this so that they won't do business with her in 
the future.

It all works out though, since the money I had for 
the cels from her (and I had intended to pay lump 
sum and bypass the payments... but she won't know 
that cuz she never even ASKED me.)  Went to this 
AWESOME Original BG Gargoyles pan cel!!  YAY ME!