OT: Credit Card charges after original invoice

[Tyler Aviss]

About a month ago, I ordered a HD monitor (basically an HDTV without
the tuner) from TigerDirect. The original invoice included the
shipping costs ($0) and PST/GST, which I authorized for purchase and
was charged to my Visa. One month later, I received an email from TD
stating:
  Your order shipped on 6/22/2009 and is on its way to you
  MONITOR (LCD OR CRT) DISPOSAL SURCHARGE  (CA BCDS 008 CA )

This charge was not on mentioned my original invoice, nor did I
authorize it to my card. While companies are required in various cases
to charge a "disposal fee" for certain electronics, standard practice
is to either include it in the price, or charge it in the original
invoice. TD argues that if I had returned the TV, they wouldn't be
able to return a gov't fee, so they charge it later

Can anyone comment as to whether charging it a month later is legal if
not included in the original invoice. Seems to me that Visa is
probably going to have them for lunch for an unauthorized charge, and
the competition bureau is probably going to look dimly on this as well
(as not listing total costs on the original invoice could possibly be
deemed anticompetitive).

Comments, suggestions?
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