I replied to a few posts but I never got any responses?
Sometimes emails end up in people's spam or junk mail folders so make sure you check the messages page and your spam mail folder for replies (sadly it's impossible to know if an email ends up in a recipients spam mail folder). And it never hurts to resend your message if you don't hear back within a day or two.
This can also happen when someone posts a popular item that causes them to get a lot of replies. Rather than reply to everyone, people often only reply to the person they choose to gift the item to. It's always up to the person giving away an item to choose who they want to receive their item so responding first doesn't mean you'll receive an item. Your best bet is to always send polite messages and be clear about when you can collect.
Other times, you won't receive responses because people forget to mark their offers as gifted. This causes their offers to stay published when they should have been removed. To help prevent this, posts are automatically removed from the listings after 90 days.
And a lot of posts get claimed within a few hours or days of being posted. So you're more likely to get a response if you reply soon after a post is published. You can see new posts more quickly by getting the digest emails more frequently or creating email alerts or by enabling push notifications.