Home loan interest rate jumped from 8.66% to 11.25% in just 2 weeks.

FNB is not giving me any joy at all, its problem after problem. i was approved for a home loan at an interest rate of 81.66% which was still high but i could live with it, all the steps were conducted until today when i got the final quote with the whooping 11.25% rate. i understand that there are many factors that involved but to jump from 8.66% to 11.25% in just 2 weeks is not justifiable, this is so ridiculous or is it a way of denying me credit? can someone please me a reasonable explanation as to why the interest rate abruptly jumped to 4% above the current prime lending rate. i am really tired of complaining about being treated unfairly. i checked other clients reviews and many of them were complaining about +1.75 rate, mine is at +4%, this is shocking. they say this is the good time to buy a property but FNB is making my life a living hell.