The first word can be 6 letters as it should be Rockin' but should the last word be 4 letters? Plus there are still missing letters (only one S for example)
I'm sure scorpiojo has it with "Rockin' around the Christmas tree" which is (6,6,3,9,4). There must be a typo either in the original or wimp's transcribing of it as there is still a C and an S missing from the anagram.
Spoke to the person about this and it is an anagram.The answer is "rock'n around the Christmas tree" I didn't think it was an anagram because there wasn't enough letters,so the person who set this question got it all wrong.Thank you all for your time and scorpiojo thank you for the correct answer!