INCREASE IN EXCESS

I joined AA insurance for car, household and building insurance. I was given an excess of approximately R 4,000 regarding additional excesses only, all other excesses were waived(R 0). I took the policy with them even though they were more expensive than other companies thinking that they will be a reputable company. A few days ago I received an email from the underwriters stating that my excess has increased now to a ridiculous R 15,000 due to other clients claiming. I have never claimed from AA as yet but my excess has increased to this RIDICULOUS amount and the reasoning MAKES NO SENSE WHATSOEVER. I am completely disappointed with this service. I called to try and decrease the excess and was told its not possible. What type of service is this? How can I be a valued client if you intentionally try to get rid of me.