The customer asked me the price of the product, and I verbally quoted a rough quotation. The customer said I didn't mean it. What should I say?

Don't say that your oral quotation is similar. Even if you show him the factory quotation, some customers will say that your factory is not sincere, which is not even a means, but a normal negotiation means. Don't think it's unnecessary to look inferior to him just by asking him to buy goods. As long as you clearly tell him your company's product information and acceptable quotation, let him consider the rest. If it is profitable, he is a fool not to do it.