Exorbitant increase

My premium has gone up by more than 200% even though I have not put a claim in. I have had insurance with them for a number of years and cut it to fire theft and balance of 3rd party while I was out of the country for 6 months this year and car was locked up in a garage. On my return I requested that my fully comprehensive insurance get reinstated. I did not accept the increase of more than 200% from what it was up to April this year yet the money has been taken from my account. I have to add that another company is prepared to insure my vehicle at the original price I paid Momentum prior to my travels. I just wanted to give momentum the opportunity to relook their charges. I also think there should be some sort of recourse for us against such drastic increases. Is there a ombuttsman to report this to