Blacklist by domain feature desperately needed

I set up ePrint for my elderly mother. She sent 1 parcel via Parcel2go and despite my dire warnings somehow allowed P2Go to learn her ePrint address. Now she is getting regular massive marketing Emails from a 3rd party marketing co. to her printer. Simples I thought, I'll log into the ePrint account and use the blacklist feature to block the originating domain (sender email addresses vary per item but are all same domain). WHAT blacklist feature? There isn't one! Please urgently add it as this would suit our needs best and it needs to have a 'by domain' option too.