Hello,
If few of your sites mean different projects, you need separate licenses. We are working according to ThemeForest license policy, here you can read – https://themeforest.net/licenses/terms/regular , more information about what does it mean 1 project, you can get via their docs or support.
Purchase a new license via ThemeForest, then you will be able to use it and complete the project, right now it has the best price – https://gyazo.com/326ef075406d1265678caf99d3956762 https://themeforest.net/item/xstore-responsive-woocommerce-theme/15780546
Regards