I apologize for the experience you're having with your contacts! We would be more than happy to help you through the steps of deleting contacts from a list. You can deleted these contacts by opening the list you're working in, selecting the contacts you want to delete, and then choosing more actions at the top of the list.
Under more actions is the option where you can either remove the contact from this list or delete them from the account. Removing contacts from a list only removes them from this specific list. Here's a helpful FAQ we have with the directions listed there as well.