It is easy to deal with Honda dealers. Honda has pretty restrict policy on them. Here is what you do:
1) check with other dealers and ask how much it will cost. You just need to call them about this.
2) If it is much different, go back to that dealer and talk to the service advisor who handled your case.
3) if he does not take care of this, you should talk to the manager to complain about it. Tell them what you want. Be prepared. If the problem still not solved, tell them you are going to call the regional manager about this. This could put them in a very awkward situation. They can get fined because of lying or bas service to you. The service advisor could lose his job for doing this at least he will lose his bonus for this month or quarter.
The may not give you refund but something like a free maintenance, which usually worth several hundred bulks.
Good luck.