I was ****med by booking.com

I am very angry, annoyed and helpless right now. Booking.com is a **** and they don't explain everything in their website. I made a booking on the 31 August 2026 of R3780 and they said free cancellation. On the 2nd September I received a call from the property I booked in, they wanted me to top up money. I told them that booking.com did not explain that on their site. The lady from the property said she will cancel my booking, I said no problem. She cancel it and said booking.com will refund me. I received an email that they will refund me R480 and I paid R3780, what happens to rest of R3300. They can't charge me so much for cancellation. It's not even 10% but on their site they said free cancellation. I hate booking.com, I would never ever in my life use it.