If that is a copy and paste of the real email, which I really hope it isn't, you'd have to of been born yesterday (phrase won't make sense to non-English people) to be stupid enough to pay for that, the fact that 'downloaded' and 'illegally' were both spelt incorrectly shows how likely it is to be from an actual lawyer.
If that's just you retyping the same words, I'd still tell them to do one (or even better, ignore the email), no details of the song in question or when it happened and why $450? Lol, not even worth your time of day.