DS Original (phat) battery wont fit

I bought a DS Original battery on amazon with the specs 3.7v 850mAH and marketed as ntr-003. Although it wont fit into the DS, and it looks about a mm thicker than the original bat and the corners are more squared and sharp making it not possible to push into the holes beside the terminals.

Here's the battery on amazon: https://www.amazon.ca/gp/product/B0DCZ6FGVW

Help would be appreciated. I asked for a refund or help and they offered a refund and that I could keep the battery... so if I can still use it that would be nice.