Replacement battery not accepted

Did you follow this guide to the letter? MacBook Pro 15" Touch Bar 2017 Battery Replacement

Somehow I suspect there was some confusion so you got your defective battery back by mistake. You’ll need to talk to the iFixit store folks. This time place a label on the battery that makes it clear its bad and it well secured.

I'm not sure this will help but I had the exact same problem with my late 2016 15" macbook Pro. After I installed the new battery, all I got was the red battery icon. The start button did nothing. How frustrated I was! I felt like trashing the whole thing. The next day, when I was more level headed, I decided that I'd take another look. The step by step directions, I think, are spot on with the detail and photos. Part of the instructions include removing the logic board which is quite a project in itself. Well when I inspected my reassembly work, I discovered that the tiny little connector for the start switch was tucked in underneath the board and not connected. When I reconnected it, everything worked perfectly fine. I hope your problem is as simple as mine to fix. Good luck and let me know.