Just terrible. The invoice seems legit, but reading the small print on the back tells you how sly this company is.
It says in the "Cancellation Policy" - We offer a 10-day money back guarantee from your initial WebsiteBackup plan sign up date. Sign up date is considered the date WebsiteBackup receives your payment. After the 10-day period, there are no refunds. However, you may still cancel your account at any time.
Bottom line
This is a shady company. The method they use to get customers is unethical. If you have received an invoice from them for the first time and don't ever remember opening an account with them, DO NOT PAY THEM.