1. Tech conventions are a good place to begin your search.
There are tech conventions constantly being held in many places all over the United States. Most cities that are a decent size have them on a fairly regular basis. These conventions are filled with drone enthusiasts who are very wired into that hobby. They will be able to tell you all of the best stores and sites where you will be able to obtain the parts and accessories that you need to keep your drone flying great.
2. Blogs are another great place to get the drone info you are seeking.
Blogs are written every day on a wide variety of subjects. There are a considerable number of blogs that focus solely on drones. Seek out these drone blogs and read them thoroughly. There is a good chance they will be able to set you on the right path in terms of where to do your shopping for parts and accessories for your Vortex Pro. You can also write to the person who runs the blog and ask him questions directly if you require additional info. The blogger will most likely be willing to help a fellow drone enthusiast.
3. Talk to other people you know who own a drone.
It would be a good idea to get in touch with other people you know who are involved in the drone hobby like you. It stands to reason that they would be able to give you some insight into where the best places are to buy drone parts and accessories. Anyway, it will not hurt to ask them. They might give you some info that is helpful to you.