A week after I bought the tree from Walmart, a few of the leaves started to turn yellow and get brown spots. The remaining unsold trees are doing the same thing. I know this because I work in the Walmart garden center where I bought this one.
Brown Spots on Leaves
Is this a fig tree you're talking about? If it is, here's an article about common fig diseases: https://www.gardeningknowhow.com/edible/fruits/figs/common-fig-tree-diseases.htm
As you can see, there are a number of possibilities. Take a few leaf samples to the Extension Service for analysis. This link will help you locate one: https://www.gardeningknowhow.com/extension-search/
Normally I would suggest the return of a diseased plant to the store, which should refund or exchange. The grower is ultimately responsible for producing disease free products.