Slugs killing all seeds, seedlings

It has become almost impossible to grow any plant from seeds in a particular area, because slugs are eating up almost all the seedlings. Most of the pest killers for slugs are not working, the slugs continue to flourish.
Online some websites said that egg shells could be used, however adding egg shells has not made a difference in one pot there are 30-40 slugs attacking any plant which will grow. The egg shells should have damaged the soft body of the slug, in reality it has not made a difference.
Any person or organization who can supply chemicals or suggest a method to get rid of the slugs can send an email to info@textads.in