I just use horticultural charcoal from the garden section of a box store (I'm not sure what home improvement store is in UK). It comes in small pieces and it is cheap dusty stuff, but works

I try to grow tons of roots and I think roots are the most important thing on a paph. They are good paphs if you can lift the plant up without the pot falling off.

It doesn't sound like you rotted them, so I am not sure. Perhaps they were rotted plants that were repotted and sold that way