Not from me!

I've just spent the day in the garden and decided to check my e-mail to find that 3000 messages have been bounced back to me as though I'd sent out a pile of spam from my domain e-mail. Clearly someone is sending them out using a nonsense name @juniper-games.com. Presumably, because the bounces are coming back to my default mailbox there's no way to trace who's sending them?

I f any of you get any crap that seems to come from a Juniper Games address, please ignore it as it's not me. Honest.