Credit acceptance RIPPED US OFF!!!!! South field Michigan

 You fail to understand . I disputing their policy , but I specifically wrote forprincipal only on the check , if they could not do it they should have notified me that they could not do it and return my check. SO no one ever said that they told me that it would be applied the same way as a regular payment.

Take the time to learn about loans and interest. Do some research. Based on your very own post, you made a $2000 lump sum payment to the lender that you had applied to the outstanding principal balance.  When you do that, it doesn't stop interest from accruing.  In a simple interest loan, interest accrues daily.  When you make a lump sum payment to the principal it reduces the principal amount but does not stop the interest. 

So yes, if you make a lump sum payment, your regular payment is still due on the next due date. This is normal. The payment is the same amount, but the portion applied to principal is a little larger because you made the lump sum payment. However, if you failed to make your regular payment, then more interest is due because there are more days between your last payment and your current payment. Go back to your loan paperwork and read about the allocation of your payments. Because you paid late (gathered from your post) you now have a late fee and more interest to pay.  

There are lenders that will apply your $2000 payment toward future payments if you don't specify that the lump sum is to be applied to your outstanding balance.