These people used to be called Peverel, or Peverel-OM. They are diabolical. I think this all relates back to when they were part of the money-grasping Erinacious Group. They certainly have the feel of a private-equity financed operation, complete with grossly-understaffed, over-centralized call centre in some cheap backwater of the UK.
Somehow the service charge on this block is higher than any comparable block I've been involved in.
The good thing is that they have a passable website complete with e-commerce for paying service charges.
What agent could do to change your mind?
Answer the phone promptly. Act to control expenditure, particularly admin type expenditure, in the management of the block.