Complaint Review: Castle Credit Corporation

We borrowed 2500 dollars for a water system for our house. We borrowed in December 2010 and it was paid off April 22nd 2011. No one was capable of explaining why the pay off had a finance charge for the month that would have a zero balance. So we paid because the CSR said wait and see if they prorate it sinced we paid 2 weeks before the payment was due. Now we have a bill that says "pay of balance good thru 6/5/2011" for 70.42. On a balance that was paid off in April! I was told by another CSR today that the people that confused us on what was due will be dealt with but we should just pay the 70.42 so they won't keep billing us and extra 35.42 a month on our zero balance. I am so frustrated that they think this is legal. Some one needs to investigate their business practices. Did I mention our contract said 17% interest per month, but we are told that it precalculated to a certain amount 17% of a zero balance is not 70.42! We can't take another rip off establishment trying to take our money and ruin our credit because they are crooks.