This is Avril we're talking about. She already got burned by RCA with Goodbye Lullaby. She is NOT letting people walk all over her this era. If Martin Johnson burned bridges with her, she's not gonna let him ruin this era.
I mean what if he refused the release, then she has no chance and needs to rerecord
If he worked on the song specifically for the record under contract then the label can do whatever they want with it as long as he's credited. They own it if that's the case.