Reflecting an adjusted 2019 Illinois tax refund in my 2020 tax return
I used TurboTax to prepare my 2019 IL tax return, and accordingly I claimed for $545 tax return. However, IL tax department sent me a letter after a couple months, in which they provided explanation for some corrections, and they ended up paying me $99. Unfortunately, I didn't realize the issue at the time (actually, I thought they are giving me an additional $99 on top of the original $545, but after a while realized that they are only paying me the $99). Furthermore, looks like I have lost the letter from IL department of revenue...
I have two questions now:
(1) Is there still a chance to revisit the discrepancy for 2019 tax return and possibly ask for a full refund or is it too late to act on this? For example, is there a way to request for the 2019 correction document online or via mail to check the issue again and request for a fix?
(2) Aside from fixing (or not) the 2019 tax issue, how should I reflect this adjustment, namely the actual 2019 IL tax refund payment, in my 2020 tax return in the TurboTax, both for federal return and state return?
FYI, I am not filing any IL tax return for 2020, since I didn't live in IL and didn't have income from IL during 2020. I'm only filing for CA tax return for 2020.