<human>: Can you summarize the given text in a few sentences?

So my first car buying experience is not what I expected.

I bought a 2010 Mazda 3 s grand touring from a local dealership.  When looking over the car before purchasing I notice condensation under the passenger headlight (it rained earlier in the day) and the bottom skirt was a little damaged.

<Fast forward to the contract signing>

They hand me a repair list of all the things on the car they are going to repair:
"1. Ding in rear passenger door
2. Scratches on back bumper & side molding
3. Test batteries / replace if needed
4. Have service look at passenger headlight for condensation. 

I hereby accept this WE OWE with the understanding that this is valid for 30 days from date of issuance and must make an advance appointment with the service department before the above work can be performed."

<fast forward to today>

I sent it to the service department to get above things repaired.  When they called me to tell me my car was ready they said the headlight did have condensation inside the lense but since the WE OWE letter didn't say repair/replace the headlight, then it's on me to pay $850 to replace it.  

The fact that the WE OWE letter didn't specify to "repair" the dents and scratches, do I have a good case if I decide to take this to court?
<bot>: Bought used car from car dealership they gave me a document of the things they would repair.  They are not wanting to fix the passenger side headlight because the document says, "look at passenger side headlight"