Returning to the other store

if I bought two  of the exact same pairs of shoes from two stores, let’s say Macy’s and Marshall’s, that are completely seperately owned. Can I return the one I bought from Macy’s to Marshall’s.  what is Rav Yitzchak abadi’s opinion on this....

Cognac

Hi I want to know cognac is kosher since the prohibition is derabanan today of yayin nesech can we say it’s safek derabanan if the goy touched the wine.