Bitcoin payments generally require six confirmations to take place before the transfer is complete. Depending on the mining fee amount paid, a transfer can either be considered high priority or low priority. Since all blockchain transfers are public record, you can use this third-party service(*) to check if your payment successfully transferred. All you need to do is enter in your block or transaction ID in the search bar. Once your block or transaction ID is located, the status of the transfer will appear.
(*)Third party service: https://www.blocktrail.com/BTC