One year old Bosch AC unit where a plastic drain pain leaked because it was installed accidentally by the HVAC company instead of a metal pan which is required with an oil furnace.

We noticed leakage and were blamed by the HVAC company that it was our fault for not cleaning the unit when it was just used for 1 season. After speaking with Bosch, they confirmed the leak happened because of the wrong pan being installed.

When asking the HVAC company to replace the plastic cracked pan,

we also asked they replace the bottom metal casing that was impacted by the water leak.

Attached are pictures of the rust, etc.

While the HVAC returned and installed the correct drain pan, they did not replace the metal casing as we requested. When we asked why, they said it is just rust and they can sand it and repaint it.

Is that acceprable or should it be replaced?

Also, does this look like black mold? HVAC said it is ’black rust’.