So sorry you're going through this OP.
FWIW, I'm starting the ball rolling regarding our previous landlord keeping our deposit. They claim that the agent said the house was a disgusting mess. There were a number of repairs, replacements and other problems such as:
- recurring black mould on many walls, around the bath and plenty elsewhere (this was brought to the attention of the agent, but nothing was done about it, apart from using at least 2 full bottles of HG Mould Spray)
- repairs need done to properly seal the window sash in DD's room, with the frame, the beading on the outside of the window was falling off and agent was emailed about it, as well as a few other problems with DD's room).
- all carpets had cat urine stains that were not shifting with my carpet washer, despite numerous washes.
- rising damp in the downstairs toilet, which was causing my paintwork to peel off.
- numerous deep holes that were a result of someone drilling into the walls.
- unfinished tiling in the upstairs bathroom, as well as a hole in the wall by the tap end of the bath. It was there before we moved in, and was flagged up with the agent.
- chunks of wood taken out of some of the skirting boards around the house. Flagged up and brought to the attention of the agent.
This is just an extremely small number of prblems that were the responsibility of the LL to fix. None of those things got fixed. There was only a few problems that were sorted by the LL.
Basically speaking, our previous LL rented out a dirty, filthy hovel, and expected their house back in a high standard of repair. Given our financial and time restrictions (I was helping to look after my terminally ill dad and my frail mum, among many other things I had to do in the day), I wasn't able to reach that high standard. I did paint and decorate, but because of a major leak into DD's bedroom, that we had to call the emergency plumber out to stop the leak and put a cap on it (at a cost of £200, which only £100 was paid back very begrudgingly), that alone severely restricted our finances.
All in all, neighbours, friends who were there when we signed the tenancy agreement, all said that we were given a filthy, mould-ridden, flea-infested house to live in and we turned it around to be very much clean and habitable.
Sometimes, some landlords really don't appreciate good tenants.