Spam e-mails and you cannot unsubscribe

I've ordered items from NetFlorist for a very important person's birthday and they COMPLETELY messed up the order. Till today, no-one phoned to try and explain or resolve it. Now I keep on getting spam e-mails from them as well and although I've unsubscribed at least 4 times, they just keep on sending their spam. I will not use their services again and do not want their spam information either.