Refund from SARS withheld - no help

SARS deposited a refund into my FNB bank account at the beginning of Dec 2015. FNB is showing the money as part of my balance but the money is not available for use as \SARS has put a hold on it". With many calls and queries SARS said that the refund is due to me and there is no detials that the fund was put on hold FNB staff keep on giving me the run around saying that their SARS department says there is a hold on the payment"