Hello Eugene,
My name is Victor and I'm a generalist developer from Argentina.
Here's what I would do:
1) Using Javascript, create a request to the trepstar URL as soon as the user clicks on submit, effectively intercepting the submission.
2) Once the call has completed (successful or not), we can then follow through with the form submission, which would trigger the email being sent to you.
There are other ways, but they depend on the specific logic you require and if you have access to a server that allows scripting, in which case I could just receive the data, fire up a request to the remote server and send the email directly. This would not require Javascript.
Thanks a lot for the opportunity. Please let me know if there's any information or clarification you require from me.
Regards,
Victor