40 ILCS 5/6-185

To authorize the payment of any annuity, pension or benefit granted under this Article, or under any other Act relating to firemen's pensions, heretofore in effect in the city which has been superseded by this Article; to increase, reduce, or suspend any such annuity, pension, or benefit whenever any part thereof was secured or granted, or the amount thereof fixed, as the result of misrepresentation, fraud, or error; provided, that the annuitant, pensioner, or beneficiary concerned shall be notified and given an opportunity to be heard concerning such proposed action. The board shall have exclusive original jurisdiction in all matters relating to or affecting the fund, including, in addition to all other matters, all claims for annuities, benefits, refunds or pensions.