I bought 8 powerbanks While exiting China at security check they taken 6 & told only 2 can carry ?

I bought 8 powerbanks in china to my family & friend. when exiting china at security check they have taken 6 powerbanks & allowed me to carry only 2 powerbanks. Am I allowed to carry only 2 powerbanks..? I lost the money I have spend for that. Not sure how to get that..!! As the security people not good in English, not providing me exact reason on this & threaten me to leave immediately.