Final answer:
Do not guess when a product will be back in stock. Instead, check with reliable sources and offer to inform the customer when it arrives.
Step-by-step explanation:
Among the steps listed, the one you should NOT take if a product is not in stock is to ask your co-worker, then randomly guess a date in the next few days when the product will arrive. This is unprofessional and can lead to misinforming the customer, which may result in a loss of trust and credibility. Proper steps include checking with the manager or consulting documents like the wholesaler notebook that can provide accurate information on when the product is expected to be back in stock. Additionally, asking for the customer's name and number to inform them when the product arrives is a good practice that shows customer care and service.