NO EXPLANATION FOR MASSIVE INCREASE IN HOME LOAN

I NEED URGENT INFORMATION ON MY BOND AND WHEN CALLING TO YOUR CALL CENTRE THEY GIVE HALF INFORMATION AND KEEP PUTTING ME THROUGH TO DIFFERENT DEPARTMENTS, ALL I WANT TO KNOW IF WHY DID MY BOND AMOUNT INCREASE SO HECTIC WHEN INTEREST RATE ONLY WENT UP BY 2,76% WHEN WE TOOK OUT BOND WE PAID R4200 WITH INTEREST ON 7.490% NOW WE ARE PAYING R5332.14 WITH AN INTERST RATE OF 10.25% IT COULD HAVE NOT BEEN R1100 EXTRA IN INTERST RATE CHARGES WHEN IT ONLY WENT UP 2.76% EXTRA !!!!! I NEED THIS SORTED OR MANAGEMENT TO CONTACT ME ASAP