Villagers have lost the battle to save their post office, which is one of 25 around the country to be axed.
The sub-post office at Keymer, near Hassocks, will shut next month as part of a national restructuring programme aimed at safeguarding urban branches.
Gales Drive sub-post office in Three Bridges, Crawley, will also close on February 15.
The Post Office said there were too many outlets competing for too little business with increased running costs.
But campaigners say the elderly residents in Three Bridges and Keymer will be hit hard by the closures.
There was strong opposition to the closure in Keymer, where campaigners have been fighting for more than ten years to keep their post office open.
Resident and firefighter Trevor Davey, vice-chairman of the Hassocks Amenity Association, is frustrated by what he felt was an inevitable closure.
He said: "As far as campaigning goes there was very little we could do because there is another post office not far away in Hassocks.
"The way benefits are paid is changing - people have them paid directly into their bank accounts.
"But for elderly villagers it will be an upheaval. They may not know the other post office and will find it confusing to fill in forms to change the way their benefit it paid."
Dennis Malt, a Three Bridges councillor, said the closure of Gales Drive would put an extra strain on nearby post offices.
He said: "There is another at North Gate, but there are often queues coming out of the building and down the street, and that's before Gales Drive has closed.
"Local post offices are a place for social gatherings as well as buying stamps."
The decision comes after a month-long consultation by the Post Office.
Drew McBride, head of the area for the Post Office, said: "We fully appreciate the concerns and have taken account of them.
"However, the issue is not about the future of an individual branch but the overall viability of our urban network.
"No one likes to see the branch nearest to them shut but even with the closure of Keymer post office, customers will still have reasonable access to alternative branches."
Hassocks and Ditchling post officers are about half a mile away.
For Three Bridges residents the nearest branches include North Road, half a mile away, and Northgate post office, which is under one mile away.
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