Dental insurance/ Aspen Dental Question

I’m so confused here and I feel like Aspen isn’t giving me a clear answer. I had a scheduled root canal and crown. My insurance is quite good and covers a large portion of the procedure. My out of pocket should have been $257 but Aspen charged me $3800 and now my balance due is showing a negative amount. Why wouldn’t they have charged me what I owe based on my insurance. Do I get that money back?