Whilst it's too late now - replying may not have been the best idea.
If it's the standard AFACT infringement notice, it was sent to your ISP as a date / time / IP Address, on behalf of MGM (ie not from MGM itself) and they've (your ISP) correlated that with your connection time and forwarded it to you.
At that time, the sender of the infringement notice had no information about who you were.
By replying you may have given AFACT (or whomever sent it) that contact information and effectively confessed to the copyright violation. They are now more able to take legal action against you directly, should they choose. Eg to make an example.
I would suggest to anyone else who receives a notice, that unless it's directed to them specifically by name directly from the organisation (ie not relayed from your ISP) that they do not reply. If they are doing what the notice alleges, and it's illegal, they should certainly stop it. But don't reply.
no subject
If it's the standard AFACT infringement notice, it was sent to your ISP as a date / time / IP Address, on behalf of MGM (ie not from MGM itself) and they've (your ISP) correlated that with your connection time and forwarded it to you.
At that time, the sender of the infringement notice had no information about who you were.
By replying you may have given AFACT (or whomever sent it) that contact information and effectively confessed to the copyright violation. They are now more able to take legal action against you directly, should they choose. Eg to make an example.
I would suggest to anyone else who receives a notice, that unless it's directed to them specifically by name directly from the organisation (ie not relayed from your ISP) that they do not reply. If they are doing what the notice alleges, and it's illegal, they should certainly stop it. But don't reply.
prk.