failure to pay or late payment may be a sign that they are in financial difficulties. I would seriously look for alternative employment. This happened to my husband when a company failed to pay him as they went into liquidation. He had no salary at all but couldn't claim benefits as technically he was employed.
I would also let the bank know about the delay in payment and request a formal overdraft to cover the direct debits going out so they don't bounce as this will cost more.
I would also go to your boss and highlight that you will be passing on any bank costs to them if their late payment results in bank charges. Keep it to a statement of the facts and maintain professionalism if at all possible.