I bought the D&D essentials kit (Dragons of Icespire Peak) months ago, but threw away the D&D BEYOND CODE to access online digital maps.   I do have the receipt and the store I bought it from tried to help but it appears each code is unique and they couldn't just give me one from an unopened box.   Where can I reach someone to help me get a replacement code?

I think you are just out of luck. That code was your proof of purchase to DDB.

It is like you bought a game and threw away the pieces, and now you are trying to get replacement pieces.

Also... I lost all the pieces. (kidding).

Thanks

Is there a customer service or support contact email address for D&D beyond?  Maybe someone will take pity on me. 

At the bottom of the page. "Contact us"

Good luck.