Motorhome Insurance

On Nov 1, 2012 we paid GMAC $520.00 for insurance on our RV and Car. In the middle of the year we received a notice that they are now National General Insurance Company. Heard nothing else from them. I’m wondering why haven’t received any payment notices. I go on line to check it out I see my last year’s statement or whatever, this is something we have not received before I have the letter where they thank us for the payment and I have the policy. This shows the $520.00 I paid plus above it, it has $1300.00 but nothing due. Go to this year’s renewal it shows $1340.00 due Nov. 1st. I call them I was told that they made a mistake on last year’s cost and they just absurd the difference. At no time did they let us know of this. I was also told that our statement was mailed out on Sept 29, 2013 never have seen it yet. So we are looking for insurance right now and the quotes are all over the place.