One of the unforeseen reasons for a slow-pay or worse yet an account that doesn’t pay at all may be due to the business having not defined to its customers (and employees) the company’s credit policies. Confusion can lead to inaction which means you are at risk of not being paid in a timely fashion, or not paid at all.
Make sure payment schedules, payment dates, penalties for late or non-payment are clearly stated in your contract or agreement, and if applicable make sure it is signed.