Booked a Guest House in South Africa

I booked a guest house in South Africa through booking.com in December 2020. When myself and my team arrived, it was not what we had booked, we were a team of 6 adult men on a company conference trip, therefore we booked three rooms of 100sqm (supposed to be huge) with two double beds inside each room. When we arrived late at night, they had given us 3 x rooms of around 15sqm each with one double bed in each room and had no more rooms to assist us. As it was late at night we had no option but to take the rooms and have some adults share a bed and other adults sleep on the floor (that were not comfortable with sharing a small bed, or against their culture). The next day we left the guest house, as they could not give us the rooms that we had originally booked due to being at full capacity and over booking their rooms. Therefore we contacted booking.com, and booking.com told us they would refund us, as their policy is either an equivalent room or better (which we did not get). Since then booking.com has used every excuse not to refund us, with their latest argument being that the amount we payed was a value in Rands but our bank statement (yes we had to send our bank statement proving we paid the guest house) shows a value in Meticais. seeing as we from Mozambique our local currency is meticais and when our bank charges us it is in meticais. But this is very common as wherever one travels in the world they can pay on a card machine any currency, and then the clients bank will convert that currency into their local currency on the spot rate plus whatever the bank charges. Booking.com has told me I am the first person this has happened to?? They even asked us to get a stamped letter from our bank, for our bank to state what amount entered the bank in ZAR (South African currency), and what exchange rate they used to translate to the value showing on my bank statement in Meticais. After much talk with our bank we managed to get this, now booking.com has told us they unfortunately cannot assist, as our bank should of charged us in Rands (ZAR), and our bank statement should show the Rands amount, which is impossible. Therefore we had to just accept the 7,480.00 ZAR the guest house and booking.com basically stole from us. I told booking.com they should have a disclaimer stating they don't recognize certain currencies from certain countries, and their hosts should not accept cards from certain foreign countries then. Booking.com just said whenever we get quoted a currency, we must just pay that currency, therefore if you are traveling, make sure you don't arrive at a foreign hotel without drawing the local currency first, as booking.com won't recognize your payment otherwise.