My Booking.com Hotel Reservation Got Canceled in Italy

I booked five different reservations through Booking.com for my trip to Italy and paid for all of them in full, a month and a half in advance. I encountered issues with four of the bookings.

I had a reservation at Oltarno Suite in Florence from April 8-11 (Reservation No: 4022440980, PIN: 4880). On the morning of April 8, the hotel contacted me via WhatsApp asking about my check-in time. I reiterated that it would be between 10 PM and 11 PM, as previously mentioned. They informed me of a €45 late check-in fee, which I hadn’t noticed during the booking process. I didn't want to pay this additional fee. After discussing with the management, they insisted I pay it by 5 PM. At that moment, I was in Venice and told them I could pay over the phone at 7:30 PM, then head to Florence, arriving in three hours. They asked me to confirm on Booking’s messaging system, which I did, but I received no further instructions or address. I tried calling twice but realized the management had blocked me. I ended up spending three hours looking for a hotel that night. The next day, Oltarno Suite didn’t contact me, and I found out they had taken and then refunded the deposit, but they still kept €298.21 of the €387.21 three-night stay, excluding VAT. I never stayed there, but they kept the full amount because I didn't agree to the late check-in fee.
I've been contacting Booking.com for a month to get my money back, but they haven't helped or refunded me. There's no clause in the contract justifying this charge, and they know I can't enforce my rights, so they've made no effort.

Even if they offered me a free room or upgraded my Genius level to 10, I won't use Booking.com again.