Impossible to unsubscribe from Netflorist mailing list

I made the mistake of placing an order with Netflorist. Since then, I have been spammed with daily emails from them, despite not subscribing and then unsubscribing 5 times and phoning twice to complain. It is impossible to get off their mailing list. I strongly recommend never giving Netflorist your details. You become trapped in their marketing system forever. What a disgrace of a company