Raising premium

We've been Infinity customers since Jan.08,when my husband joined the ARMY,we were living in Florida,and paying about 130.00 a month for two cars,a "96"Ford minivan and a "98"Ford mustang,and then we were assigned to Fort Riley ,KS, in Sept.When I called to give them my new address,the lady took my info and bid me good day,about a week later I got a letter in the mail saying that my monthly payments had been adjusted and we would now be required to pay 533.00 dollars a month until our policy expired in Dec.Just because I changed my address,we were not involved in an accident,we didn't get any tickets,all we did was move to a different state.I think it's crap that they can charge so much just for a change of address,who in their right mind would pay that much a month?Who has that kind of money? When I called to find out what was going on the lady told me"Well you only have two more payments left" like that was a good thing,the total of those two payments are more than i've ever had to pay for a year policy,I think it's funny that they thought we were actually gonna pay that.needless to say we're not Infinity customers any more.