Don't feel bad about the interest rate. They did the same thing to me, the only difference is I noticed it, made a comment about it. I signed the loan at a higher interest rate to get the rebate. I put down a decent downpayment and have really good credit but still got a crappy interest rate. However, I was already pre-approved with my credit union with a good rate so I'm going to make two payments and refinance. I'm not worried about it, they will not be getting me.
I had a salesman tell me point blank, "They will tell you that you have to make four payments but you only have to make two."......ha, it sounds like some of you only made ONE, wow.