I absolutely love my justin boots. I have these ones : Justin Boots Waterproof L9034 BROWN COWHIDE
I've had them for.. about 2 years now and they are still going strong. I wear them practically everyday. Riding, through rain, cleaning paddocks, and even in the lake! Yes, completely under water.
They are super waterproof. After being in the water, just give them a quick oil down, and they look brand new! The inside liner is extremely breathable and supportive. They are the comfiest shoes/boots I have ever put my feet in.
They still are in awesome condition, with barely any discoloration at all, and the liner still looks brand new.
I'm really surprised that the store wouldn't at least give you store credit, or trade for a different pair. Boots should not do that in just one month! :O