I''m waiting for a hearing for support modification, in the mean time the state is taking out my old rate for my ex for child/spousal support.

Since you are waiting on a hearing, that means that you have a petition pending in court.  That is the good news; the problem lies with the delay in getting to that court date.  It may be that you need to secure an attorney.  It may be possible for the attorney to advance the court date or enter into an agreement with the other side (private attorney? ex-spouse? Public Aid lawyer?). The way support works in Illinois is support is due as it come due - weekly, biweekly, bi-monthly.  Only a court can alter that process.  As such, each pay period that comes to pass requires support to be paid in the amount set forth in the order then in force.  The law allows for the order to relate back to the date of filing.  Such a result would then create an overpayment (provided the court agrees with you).  These overpaid funds can be ordered to be returned to you or taken as a credit against your future support obligation (at the new and presumably lower payment amount). Each county and courtroom tends to have its own quirks and procedures.  To best protect yourself, it is suggested that you retain an experienced family law attorney.  First, the attorney can confirm your computations as to support.  This is important as certain statutory procedures need to be addressed to allow for any reduction.  Additionally, the attorney may be able to expedite the desired reduction.  Finally, the attorney can assist in proposing the most beneficial method of addressing any imputed overpayment due to the relating back of the contemplated reduction. If you are unsure how to locate such an attorney, most county bar associations have lawyer referral programs.  That would be a good starting point to find an attorney.