reply to case id

Hi. Apple replied by email to a query I raised with a Case ID.

I'm not satisfied with their response and wish to continue the conversation.

Replying to the email is useless because the email account is unmonitored.

When I call up the Case ID on the Apple support pages, it simply tells me what the issue was but no ability to reply back. Please can someone help. I tried to be crude by creating a new case but my message being my reply to Apple's exceeded character cap. All I want to do is explain why I'm not satisfied!

Many thanks.