Pioneer Services A Division of MidCountry Bank

I have a loan through Pioneer Services. I have had this loan since September 2012. During that time I have made 8 payments. Even when I have only been required to make 7. I am a month a head. But they have reported to the credit company that I was 30 days late twice. When I was not. It has since dropped my credit score. I tried talking to them telling them I was a payment ahead and they answer I got was you must make a payment every 30 days. I then told them I had and there was one time that it wasn't made in a 30 day time frame but I was still a month a head in payment. and should not have been penalized.