I received an invoice when I first registered with PM via e-mail including detailes of plan&add-ons as well as how much tax was charged.
I was expecting to get the same one when I was auto-charged this time, but apparently I will have to PM moderator to get an invoice and it takes dayyyys.
Please let users to download the invoice in their self served account or simply just send it to their e-mails. I believe this is not very difficult thing to do.