How about telling us the addresses in question, or even better, the supposed TXID's?

The point of sending a second transaction is because that second transaction would get higher priority, as it has a higher fee.

Let's call them Transaction A and B, you didn't have a fee on A, so you send the exact same transaction again, with a fee, and that became B

Because B has a higher transaction fee, it has a higher chance of getting confirmed. Assuming both transactions are equivalent, it shouldn't matter which one confirms, as only one should confirm assuming the inputs (think of them like coins) are the same. When one confirms, it cancels out the previous one because the previous one would become a double spend, thus become invalid.

When that happens, you may get the original transactions coins back. You may need to start Bitcoin with -rescan (google it) before it will detect that transaction is now invalid.