cancel send of read report, How?

[Guest]

I have an overseas "free" ISP account (Freeserve.co.uk)
that I use occasionally to access the internet by dial-up
while visiting UK. I still need and am able to recieve
from that account by using my home ISP but can only send
by dialing a special toll number from within the UK.
Anyway my home computer is trying to send a read reciept
to the return email for that account and I therefor
continually get popup "send and recieve" error messages.
Obviously I cannot see the read reciept in my outbox, so
I cannot cancel it there, nor can I reset the account to
use as I cannot see the message.
How Ccan I cancel the sending of a read report?
Also is there anyway I can set my home computer to
automatically reply to messages from freeserve using my
default home ISP account?
Many Thanks
Iain