Royal Mail said it did not plan to change the postcodes again
Villagers who have had their postcodes changed to ones in Coventry despite being in Warwickshire have been picketing Royal Mail's headquarters.
People living in Hawksbury said having their postcodes changed from CV7 to CV6 was confusing as it showed the village was part of Coventry when it was not.
A group of villagers protested at the firm's London headquarters earlier.
Royal Mail said the change was made for "operational efficiency" and saw no grounds to alter the postcodes again.
Coventry is covered by the CV1 to CV6 postcodes and Warwickshire by CV7 and above.
One of the campaigners, Steve Vick, said that the situation had also been confusing for local police forces as Coventry was in West Midlands Police's area, while Warwickshire was covered by Warwickshire Police.
Mr Vick said that when someone reported a crime recently, the police had to check the postcode lists to see if they had responsibility for the village.
In a statement, Royal Mail said: "The main principle behind the code is that changes are only made where absolutely necessary and only in the interest of operational efficiency.
"Having reviewed this issue once again Royal Mail can identify no demonstrable benefit to mail sortation and delivery arrangements and still feel that there are no grounds on which to make any postcode changes in this area."