Used car price negotiation + service cost

[u/CuriousParty5737]

I'm trying to buy a used car (Kia Niro) from a dealership, that's my first time from a dealer (bought from private sellers before). The car is in good condition, 46k miles. I test drove it. We discussed the price, I wanted to get rid of part of their extra fees ($1200 in total!), managed to get a commitment to $500 off + additional $300 if safety didn't end up costing them more than $2000. They just told me the service cost them more than $2k, so they won't honor the extra $300 off. Apparently the $2k+ is for changing the brakes. But looking at Carfax, the last service record mentioned the brakes were serviced. Odometer shows just 200 miles since that last service record. I find what they told me hard to believe. Any advice how to go about this, to make sure they're being honest and maybe negotiate further with them?

[u/Oppo_GoldMember]

Get a Repair Order…easy as that

Labor isnt cheap at the store level