Top loaders go a long way in stopping the bending, but it'll just happen when you play with them some time. A way to fix that is to get hold of a good 3-4 books, heavy volumes, and simply lay the foils under them (I do this when Ihave a MtG tournament and need to, for example, use Ajani Vengeant, which I only have the foil pre-release versions) for about 2-3 days.