giving me hard time to cancel my policy

Beginning of June I began process of switching my bond, all went well & my building was insure with Ooba on 27 of July I gave the notice to cancel my policy by end of August & I have given them the proof of my new signed contract that includes cover for building. They reply saying they cant cancel my policy with that information they want detailed policy schedule of new building protector. My new bond is registered on the 18/08/15. And I have asked for the cession letter from previous bond provider & that will take +/-9working day. Ooba has been reminding me that the 20/08/15 is my last day to submit the documents they want after which the 30 days process will apply. I think this is so unfair because I don't owe them anything and its my lawful right to get insured with whoever I want. I did put in notice in due time & they have been this unfair. and offering lower rate which I have declined and today is the 20th so my policy wont be cancelled & will pay 2 policies thanks to OOBa