There are three issues here.
The first, as has been said, is that the deposit must be lodged in a recognised scheme
. If it isn't, then the landlord owes the tenant a very large compensatory payment.
The second is that fair wear and tear to a property is reasonable, and unless you have caused preventable harm (so your children haven't scrawled on the walls in felt tip, for example) the landlord has a allowance in terms of taxable income to cover redecoration and it's not the tenant responsibility unless, as has been said, there is a contract term making it so. Same with professional cleaning - you have to leave the property in the state in which you took it, but unless the contract specifies, how you achieve that is down to you. Take LOTS of photos, when leaving, to prove the state of the rental.
Finally, if someone is threatening to release sensitive information about you more widely, to force you to pay them money, then that sounds like blackmail, which is indeed a criminal offence. If you have his threats in writing, in emails, that's something I would consider taking to the police. Be aware that the police are not always great at grasping when something is criminal, if it's around a tenancy, and prone to saying 'that's a civil matter'. If it's blackmail, it's not. Someone threatening to release sensitive personal information more widely, to make you pay them money, is a criminal.
I'm afraid it also sounds as if he feels you are a foreigner, won't know your rights, and can be harassed into giving him money. I would call the free helpline offered by Shelter
, who are a charity specifically and solely set up to support tenants in these situations. They can offer support and advice, for free, that reflects up-to-date law. Sadly, there is nothing you can tell them that is going to be novel. Bad landlords have a playbook, it seems.
I'm so sorry you are in this position, and dealing with this person.