Most problems can be resolved by reading the manual. Please view the page Manuals for user manuals, quick starts and pump connection diagrams.
Leaking is not normal and may be due to a defect, but this is uncommon. In most cases it’s because parts were not boiled, or properly cared for. Parts are durable but can also become damaged. If you are a heavy user you can expect parts to wear out more quickly and need replacing. Review this post on leaking.
Low output with Freemie use is a misnomer as the cups are a receptacle just as bottles and horns are. This issue is usually due to improper assembly or connection, or using the wrong size funnel. Please review this post for more information on low output.
Milk in Tubing
Milk in the tubing is a user error and can be corrected through proper use. Most often for new users, something is assembled incorrectly. For more experienced users it’s because the valve are worn and need replacing. See this important post for details.