Premium increase but payout the same

I took out a salary protection policy with [URL Removed] from 1 August 2012. I thus have a policy for 2 years and 6 months, I decided to check on my policy details last week and was completely shocked when the lady said that even though Frank increased my premiums each year the payout remains the SAME, I mean, is this even legal? All my other policies increase each year and so does the payout, how on earth and what for was these increases if not for my payout. I am absolutely surprised by this and do not wish to simply cancel my policy because I have been paying for so long and cannot see the point in loosing my monies paid?