Cancellation of Bond

I had a Homeloan with FNB which I had been paying diligently for 10 years. Due to a divorce it became necessary to change the bond from one trust to another. FNB refused to give me the same rate I had before and out of principle I registered the new bond with ABSA. The bond was registered for R1,200,000.00 of which R1,160,690.65 was still outstanding at the time of cancellation but FNB requested me to pay R1,234,931.31 in order to cancel the bond. I fail to understand how they could demand more than what was owing and even more than the registered amount. The attorneys told me not to worry and that FNB would refund me 4 - 5 working days after the new bond was registered. It has now been 10 days and no refund. When I phoned I got told that the bond is under cancellation and it could take up to 3 months to get a refund. How is this not *****ing? Who is earning the interest on MY money?