Companies that won't provide a contact number on their website. Businesses that route calls through endless voice mail, holds and can't-get-out automated phone menus. Staffers who won't take ownership of a service problem. Those are just some of the top 10 customer service mistakes that companies make, writes Hansen Lieu, director of solution marketing at SAP. Others: Customer service personnel who never show up at the promised time, companies that won't solve a problem product but are happy to sell a replacement, and service agents who merely pass the issue along to another person.