What should I do if the sales manager resigned after paying for machinery product?

I believe that some customers have encountered this situation and bought a certain company’s products (especially large machinery and equipment), but then the company’s salesman who served them resigned, and there was even a situation where the payment was over. The sales staff resigned before the goods were delivered. In the first situation, it's okay, just continue to contact other persons in charge in the company. If you encounter the second situation, it will inevitably make the customer startle in a cold sweat, worrying about being cheated. Recently, a colleague in charge of our business resigned (although our company's employee turnover rate is very low), the business has already been handed over before leaving, and the customer has been notified of the resignation, and the employee who succeeded him has also sent messages to the customer. Maybe the customer was too busy to ignore the news, and when the customer asked about the production progress of the production line for dog food that he had paid for the deposit, he knew that the business he was in charge of had left. The customer was anxious and thought he was cheated. Therefore, considering this aspect, when buying large-scale machinery and equipment, buyers should also choose a large company, a powerful company, and a company with a low employee turnover rate, so as to reduce the difficulty of subsequent delivery and maintenance of equipment, and reduce the fraud risk.