Time to dig out the paperwork on that extended warranty. You also need to understand how it works as far as payment goes. It's possible that they reimburse you rather than pay the shop directly.We bought an extended warranty when new and was told it was for seven years bumper to bumper for $1,700. Dealership says the warranty does not cover the heated seats.
You didn't say who the warranty is with. A lot of dealers will sell third-party warranties. So that extended warranty may not be with GM.