MAVRIC:
Hello and welcome to BLF. Sorry to hear about your issues with the batteries, I know it can be frustrating. Can you post the link to the Keygos you bought? I suggest you look at some alternatives and it looks like you are going to have to settle for unprotected cells as the protection circuit adds 2-3mm to the cell length, maybe King Kong INR86650E. According to China Quality Goods, these measure 26mm x 66mm. Unfortunately, most vendors don't list the dimensions. Here's a thread for you to look at that might help in choosing another battery: https://budgetlightforum.com/t/-/7473
Another alternative is to use case reducers with 3 18650 cells, at least until you find some bigger batteries that fit. If you can't wait for these to ship, take both batteries to a hardware store and try to find some PVC plumbing pipe that will work.