I found this: 3 companies who make generic Concerta
As to getting it covered by the insurance, have you spoken with anyone at the insurance Rx program to see if a certain generic is covered?
I’d also suggest going in to a pharmacy. Typically pharmacies will not disclose whether or not they have a stimulant over the phone, and rarely in person. If you go into the pharmacy physically and ask to speak to the pharmacist they may be more willing to help.