Ordering a router AFTER subscibing to Homflex

Hello, 

I have made the mistake to subscibe to a Home Flex contract without the router. Now all I have is a useless sim card. On the O2 website it seems impossible to order a router without re-subscibing to another Home Flex contract. How can I rent a router alone ? hopefully without having to call the O2 hotline or to go to a shop which I do not have at proximity. 

Thank you for your help

Aurian