The contacts are spring loaded to make contact and unless as Knottyrope indicates they are dirty they should not fail to make contact.
Another thought, If the phone is kept in a rear pocket like many people do, I would replace the battery also just in case it is damaged. Videos on the internet show the potential of fire when they are crushed. A lot of people sit on the phone and can cause damage.
__________________ If someone helps, tell them by clicking the Thanks buttonî