As an ex officer my advice would be to constantly report them. Drive the police department nuts with calls. Also try to contact the drug task force for that area. They have more authority in that area.
I'm sorry to hear that.I know it seems like they never get busted, but have the police ever raided them? About the only way to get rid of that problem is if the neighborhood makes it "uncomfortable" for both the dealer and the customers. Try speaking with your local law enforcement agency to find out what you can do. Good luck to you.
I'm afraid that been if you call the cops due to lack of man power or budget they won't be able to send cops on a wild goose chase. But if you could secretly video record the dealings (if done in the open) or how often people come and go ect. They might prioritize your citation. They might also suggest a neighborhood watch. They will give you guidance give them a chance and contact them.