Pictures would be handy if you have them.
I've removed a few figures from bases with different approaches. For metal tabs glued to slottas I used a
side cutter to destroy the plastic base and release the tab.
I've also used a side cutter to slide under the foot and cut the figure off that way. However, it is easy to damage the figure if you're not careful, and you can end up with a bit of a V-shape.
I've also had some success using a scalpel blade (Swan & Morton, so proper sharp) to cut between the foot and glue, but again, care and patience is required.
The side cutter should scale to 500 figs, but I doubt the scalpel would
