Account placed on hold with out a reason

Account been placed on hold with out any reason. Went to the bank to ask why, they said I must phone the ***** line to get answers. Only answer I received is that someone on nightshif placed our business account on hold with out any reason. No comment on why. This is month end salaries need to be paid. I have had no joy with our business banker. No one can give me an answer. Very very upset that any one can just place your account on hold with out even letting you know. Very disappointed in FNB SERVICE