As per your other thread from a while ago, check your leasehold and see what it says.
If you are certain you have complied with any requirements, and they refuse some bit of paperwork, then write and tell them that they are in breach of the leasehold agreement and give them 14 days to comply. As above, CC the council solicitor.
Add out that should they fail to comply, you will report the officers concerned, and those responsible for managing them, for malfeasance in public office.
Might be worth waiting to see what they come back with regarding your request for them to state what regulations or leasehold terms you have failed to comply with. If you don't get a prompt answer, write again stating that you have not had an answer and give them 14 days to respond.
As long as you are in the right, then you can make things very difficult for the people concerned. Once people realise that a) they don't have a leg to stand on, b) they aren't going to bully the other side, and c) it's going to cause sh*t for them, then they usually back down sharpish.