Some considerable time go I was using tesconet but found it awful so when I bought cable I changed to ntlworld which is fine, however now and again I am informed by my friends that their emails to me often show a message from the postmaster at tesconet saying they can't deliver them....the emails do however reach me OK...... it's annoying beause they usualy send the same message two or three times.... then phone.....Different people have had a go at finding this tesco GREMLIN but to no avail, everything looks in order. Anyone any idea what it could be?