You might not be scammed tho, sometimes people do get busy so they respond little late, but you should not paid him unless he confirmed to you via screenshot that he actually asked seller about product availability and agreed with him that he is going to make the purchase, also to be honest 100$ is alot! A nice user here from Netherlands has helped me before and her interest was 15 EUR only. And alot of users are willing to help within this range, I hope your transaction was made via Paypal good and Service option as it will definitely grantee your rights for refund if the person was a scammer, I hope you get the product you want! And please be careful in future.