Did Paul write other letters to the Corinthians not included in the Bible?

In 2 Corinthians (2 Corinthians 7:8) Paul writes "I see that I hurt you with my letter". Some people think Paul is referring here to his first letter (1Corinthians) some people think this refers to another letter.

There is another letter called 3 Corinthians but most scholars believe this was not written by Paul.

The truth is we don't know if Paul did or did not write a third or fourth letter to the church at Corinth