I didn't want you to act too hastily and throw out the pepperoni.
Most packages of the sliced pepperoni that I have seen say to refrigerate the contents of the package after opening. I often divide the package of sliced pepperoni into smaller packages and freeze them until I need to use them. Since meat products degrade in quality with time in storage, it is obviously better to use them sooner rather than later, whether refrigerated or frozen. Once you use your Ezzo pepperoni, you should store the unused portion in the refrigerator or freezer.