Supersonic refuses to cancel installation order request made by previous tenant(s) at my flat

I have been trying to install fibre using VOX as my ISP but SUPERSONIC is blocking my installation order with VOX because someone who previously occupied the flat (my current address) i’m currently renting had made an order with SUPERSONIC now they want me to track everyone who used to stay at the flat (my current address), and get their details then contact them so they can cancel the order.

SUPERSONIC is basically holding me at ransom not to cancel the order because they know very well that I couldn’t track the person who made installation request with them, yet SUPERSONIC is refusing to cancel the installation order request by someone who used to stay at my flat (my current address)

CAN ANYONE PLEASE HELP ON HOW TO DEAL SUPERSONIC (ISP) installation order