Are there actually areas where no courier company would deliver?
According to Wikipedia, post office has 1400 outlets in 2015, and I know they have been closing them left right and center.
The evil private sector on the other hand, is actually much better at this sort of thing. Paxi, which allows every pep store in the country to be a post office, has 2500 pickup points.
These services are actually quite cheap for a retail store like pep, as they already have a logistics network. And they can cross subsidise a bit it as it gets people into the shops.