use of commas

In the statement “Guilty as charged, but no longer”, I was told, by a friend that happens to be a technical writer, that the use of a comma is incorrect. According to “Rules for Comma Usage”,"one should “use commas to set off phrases that express contrast”. Example: The puppies were cute, but very messy. Why is my comma incorrect? Thanks Tom

No need to start the exact same topic in two threats, Thomas.
english-test.net/forum/ftopic78560.html

In this forum “English Vocabulary, Grammar and Idioms” you will have your grammar-related question answered quite quickly in general.

Check those links of this site regarding comma usage:

english-test.net/forum/ftopic78283.html
english-test.net/forum/ftopic3620.html
english-test.net/forum/ftopic3391.html

Another link to comma use explanation:
grammar.ccc.commnet.edu/grammar/commas_big.htm

Good luck.
Regards,

ozzy