[Exim] Having trouble with 'seen finish'

I am having trouble with the 'seen' filter command.
I have a filter setup so that only local addresses can send to a certain
address. If it is not a local address, then I send the originating sender
a form message, and I also want it to delete that message.
Whenever it is sent to me, no matter what address it is from, I still
get that message put in my mail file.
Here is the code:

#Exim Filter
if
"$header_from:" contains "my_address"
then
deliver "my_address"
elif
"$header_from:" does not contain "my_address"
then
mail to "$sender_address" from "my_address" reply_to "frenzy@???"
subject "blah" text "blah"
seen finish
endif

I cannot get this to delete that message with seen finish for some reason,
it always stays there.
Am I doing something wrong?
Thank you,

Randy McClelland-Bane
@Harborside Technical Support 1-800-680-8855
http://www.frenzy.org -Administrator