Schenecken Slayer has given you the answer. I too am in Fort Mistake - KZN - South Africa (where are you living?).
I make a lot of Halloumi and Ricotta and once the cheese floats in the hot (80 to 85degC) whey, I fish it out and split it to insert mint leaves. then leave it to cool down with a light weight on it, before putting it into the brine. It always comes out well. I only spoilt one batch when the brine was too hot - like yours. It didn't even turn into Mozzerella that time, just a complete failed-make!
Also don't press the curds too heavily when you first take them out of the pot (prior to "cooking") The time you mentioned (3 hours) is fine but the weight should be quite light. You will know it's too heavy if the whey that comes out of the curd is white like milk. It should be clear like lemon-juice (I amost said urine - the nurse in me!)