Shipping problem with some italian adresses

One of our customer underline that he can’t order because, having Packlink as unique shipping method, sat with a fixed shipping fee, in some italian addresses (i.e. seems in all “Calabria” region) the ecommerce said there’s no shipping method available.

How can we solve? Just to work, we created a “Unique fee” with the same prices, but it’s odd not to use Packlink…