If you have a standard issued TX order, it states (at least mine does) that you need to submit medical bills to the NCP within so many days for them to be reimbursed. If you have 2 years worth saved up, don't get your hopes up trying to collect on them.Believe me, I am not defending them. Two years for the withholding order and then the amount is wrong!! And of course, they've never done anything about my medical arrears.
Check your current order for any language pertaining to that. I seriously doubt the OAG will do anything to collect those for you. It might be up to you to pursue those on your own.