There is nothing wrong about asking for the money they owe you. Companies, and some real big ones, use accounts payable as a place to juggle their cash flow. They will keep their money as long as they can, at least until the next reporting period. You really need to be the squeaky wheel and let them stiff someone else. If this company is in trouble and big is no indication, you don't want to be holding the bag too long. Best case is they are just slow and have your money held up to make a quarterly number, worst case is they just don't have it.
