I've done quite a bit of work for them. On my most recent pay statements, they state that they pay on the 15th and 30th of each month - with a one day allowance for holidays. They cut pay dates off at the 7th and 22nd, meaning that it could take up to 38 days for payment to reach an account. The payment policy link on their Shopmetrics reads "TBA." I suspect that the "45 days" in the ICA is a CYA statement, just in case something happens with their internal processes causing a delay, they have an eight day cushion so as to remain in accordance with the ICA.
I looked back at my payment history with them and they have paid like clockwork. For a company that has been so reliable, there is no reason to panic at a one day delay. (However, I do recognize that it can be painful to not receive earned money as expected.)
Hard work builds character and homework is good for your soul.