Yes: private businesses or companies can choose whom to sell to or do business with--the law does not require a company to sell its products to any who want to buy. While certain businesses (e.g. places of public accommodation) may not deny service on certain discriminatory grounds (so, not because of someone's race or sex), any business may refuse service for reasons like the one you describe--that a member of a prospective customer's family has not paid an outstanding bill, making that person a potential bad risk.