Hi all! I’ll try to make this as short as possible. 
I work as an operator for a taxi company in a fairly small office. Our holiday year runs from end of December- end of December. Last week we were told by the directors that if we had any remaining holiday days to add it onto our clock in card, and we’ll be paid for them. I’m assuming this is due to everyone not being able to take them in time. I had 4 days remaining, so added this onto my normal hours. Payday came, (we get paid weekly), and id been paid the 4 days holiday which was fine. However the next day the office manager pulled me aside to tell me that I’d been overpaid by 1 day, and it will be deducted from my wages next week. I argued the toss, told him I knew how much holiday I’d taken as there is a book in the office that notes if staff have had holiday on a week by week basis. I’ve checked this book and worked out how many days i’d already taken etc. He argued back telling me I was basically wrong, and had a snotty attitude while doing it. He said he would check with the accountant and get back to me. Nothing else has been mentioned regarding this so I’ll just have to check my wages this week.
The other issue is a fairly new colleague. I’ll call her “Kath” for the sake of this. Kath started working for us in April, and since her start date she has had a LOT of holiday. She’s not very good at her job at all, constantly making mistakes, demanding that her shifts are reduced, calling in sick and being seen out and about happy as Larry, and just generally has a very bad work ethic. I’m not her biggest fan I’ll admit.
Anyway, due to being a taxi company Christmas and new year is understandably a very busy time for us. Kath has decided to book off the whole of this week, including Christmas Eve, Christmas Day, and New Year’s Eve. This has caused uproar in the office as she’s booked it very last minute, and a lot of mothers with young children are having to work the whole Christmas period due to not being allowed to book it off. What makes this 10x worse is Kath has used up all of her holiday days. Because she started in April and works 4 days a week, she’s only entitled to 17 days holiday. She’s already taken 20, and has another 8 days booked off. This is not fair! The office manager doesn’t know about this as he’s not very on the ball. So do I mention this to him, or just leave it? What’s pissing me off the most is I’m really having to fight for my 1 day which I’m entitled to, whereas she knows full well she’s already been overpaid and currently has the whole of Christmas and new year booked off 
Aibu?