First off, you're not far enough along to access any DLCs, if you have them. You have to finish the base game before you can access anything else. Second, since you bought a physical copy, there should be a piece of paper inside with codes for the DLC. The disc itself only contains the base game, so make sure you put in all included codes. Third, what's the exact name of what you bought (and was it new or used)? You mention the Complete Collection, but if you're referring to the Forsaken Complete Collection, as far as I'm aware, there's not a physical version of that Collection. Fourth, there is no currently available "season pass." There's an Expansion Pass, which includes Curse of Osiris and Warmind, and there's a Forsaken Annual Pass, which adds extra content on to Forsaken. You can't buy the Annual Pass without owning Forsaken (or at least you're not mean to be able to), so depending on what you actually bought, and if you put in all codes or not, will explain why you're seeing what you're seeing.