unless sold as waterproof, you need to take extra care after wearing leather shoes in rain.
In addition, again, unless sold as waterproof, all shoes will let in wetness in wet conditions.
After wearing shoes in rain, stuff then with newspaper or other absorbant material and leave in a warm dry place, but not direcly beside a heat source.
If you wear them frequently in wet weather and simply take them off and leave them in a wardrobe/cupbard wthout gibving them care, they will be destroyed fairly quickly.
The retail would have no responsibility in this case.