TPMS Light Flashing, TPMS Sensor Replaced, Light Still Flashing.

I own a 2008 Chevy Aveo. The low tire light came on a few days ago. Not only did it come on, but it was flashing. Manual states this is indicative of a problem with the TPMS system itself, and not low pressure. I took the car to the tire shop, who had just replaced my tires and valve stems 2 months prior. They tell me one of the batteries in the TPMS sensor for the driver rear is dead and the sensor needs replacing. Charge me 60 bucks, then tell me I have to take the car to Chevy to have the system "re-learned" for the warning light to stop flashing.
I call Chevy, they tell me no problem, they can re-learn it for free. When I take the car to Chevy, they say the rear sensor is still bad, they can't read it, it needs to be replaced and will cost me $120, because the TPMS that the local tire shop installed was not a GM part.
I take the car back to the local tire shop, they tell me this is "BS", there is no such thing as a GM TPMS sensor, they are all made by Schrader. They tell me that if Chevy can fix it by replacing it with a GM sensor, they will refund me the $60 I paid them to fix it. They also show me that they can read the sensor just fine, and Chevy needs to simply re-learn the system, and of course that this has never been a problem before.
So, who is feeding me bull? Is Chevy just not wanting to relearn it and sell me the same exact part? Or do the folks at the local tire shop not know what they are talking about.
I should add, I did disconnect the battery, and held down break for 30 seconds. This did not work.
TL;DR: Big Chain Tire store replaces TPMS to fix low pressure light, light still on, Chevy says it is because Tire store did not use a GM part. Tire store says that there is no GM part for the TPMS.