I am looking for a service center that can work on an ac/heat unit that requires R410A freon in it. I am in LaGrange Illinois. Thanks

I really don't know the La Grange area -- Seems to be close to Chicago -- there may be a service center
In a 20 mile range of La Grange -- You could call this Service One and ask if they work with R410A.
Maybe some industrial plants or the gas company can recommend someone -- make a few calls

Heating/AC service , La Grange, Ill - Google Search

Service One Heating & AC Inc
La Grange, IL 60525
(708) 354-4699