56% premium increase after 1 year of cover!

I took on building Insurance last year and was impressed by the quote given @ R275 for two properties so I took the cover. I was shocked to find out that as of 1 June 2018, my cover increased to R431. My cover increased by just over 56%. Is this what Outsurance does, give you a very low quote and promise no increases when you claim only to hike the price up after a year? I was told there would be an increase of 7-10%, not 56%. Outsurance, this is ridiculous and I will be cancelling my policy and will inform everyone I know who has an Outsurance policy of how you quote a fantastic price just to get the person to take on the policy. I want my money back!