Standard Bank Bond Insurance - ********** and can't reach anyone for an answer !!!

Two weeks ago standard bank sent me a document with my Bond insurance payments and the amount the house is insured for. Without my knowledge they had been increasing the "house value" by 10% annually and I have been vastly overcharged for insurance based on a the value of a property of over R 3.2 million. I addressed this and they sent an assessor to the house and have now valued the house at the correct amount of R 1.7 million. They have now resent the policy with the value at the correct amount, however the adjustment is only R202 and should be R 443. Their email comes back with an automated message saying someone will contact me and their call center says that it will be escalated and someone will phone me. (none of which ever happens) I am am also trying to get a breakdown of how much I have paid over the last 13 years relative to what this should have been.