Welcome to the community!
Sorry to hear you've incurred additional charges. Have you had a chance to view the detailed billing? You should be able to view the culprit calls in those details. You should be able view those details via your My Account --> View & Manage Bill. From there, you should be able to Save and/or Print a PDF copy of your bill. Alternatively, you should also be able to access those call details by clicking on Usage summary.
I understand your services might include the 1000 International minute promotion. If the additional charges are for long-distance calls, are you aware those minutes are only to certain Countries? Is it possible your calls were to a destination which was not included? It should be noted that the included Countries for the 1000 International minutes promotion might vary depending on when you received the promotion (see here). As far as I am aware, the current list includes:
China (including Hong Kong)
Though, you would need to verify the included Countries in your particular promotion.
You should note these forums are community-driven and not intended as a venue for customer services. If you would like to discuss those charges, you would need to contact customer service. In addition, they can also be contacted via Live Chat, Facebook, or Twitter. Those methods can be accessed via the contact page posted above.
Hope this helps 😀