Nice lady from Camden: yes, yes we have overcharged you by £350.
Me: Can I have it back please?
Nice Lady: Ah, well, it looks as though at some point in the next six months we'll issue you with a credit note.
Me: And then can I have it back?
Nice Lady: Maybe. All your accounts have to be in credit at that point. And I notice that your service charge account is still in arrears by 76p.