Exorbitant premium increases without adjusting insured valuations by Old Mutual Insure

Old Mutual Insure has a practice of passing exorbitant YoY increases on premiums without also increasing the underlying insured values on the items insured. This obviously dilutes the value of your policy tremendously. They increased my comprehensive insurance premiums with 37% and then when I complained indicated the will reduce it to 24.8% which is still completely out of line. I had no claims for past 12-24 months. The also underlying insured values remained unchanged. I am not sure what they are busy with but I suspect they are doing the same for all their clients so watch out!!!