Excessive prepaid interest?

[T Le]

We just closed on our house and got the final settlement (we live in California). The problem is in the settlement, the interest paid to lender (for the remainder of the month, before regular payment kicks in) is calculated 7 days from the day of closing. That is a lot of money that we don't want to pay for. From what I know, we're supposed to pay interest since closing day (or at most 1 day before that) only.

We've contacted the escrow service and they say take it up with the lender. I'm confused who to go after (but we do want to go after someone to get back the money). Should we press it against the lender (to refund the interest), or press the escrow company? (And by press I mean legal leverage or some way that makes people listen to you, not just courtesy asking, because that hasn't seemed to work so far).

Does anyone have any advise or has dealt with something like this before?
Thank you very much.