Over time, the charging port on the phone will wear out, and will need to be replaced.
A local phone repair shop can repair the charging port on the phone by replacing it with a new one so that it works perfectly again.
Or you can send the phone away to a repair service to have this repair carried out.
If the phone is less than 2 years old, then the repair is free.
You can try the following service:http://www.freesamsungrepairs.com/