Hi guys, I'm struggling to get crank off with this square taper puller I bought off Amazon. It came with a top hat but no idea if that is for different size square tapered thread?

Anyway, I had a go with its top hat off and the part (on the crack puller removal tool) that pushes against the spindle to get the crank off has
started to round off?

Is this normal or is this tool poor quality?