Charging issue

My Samsung Note 9 will only charge with the original one-piece wall charger.  It ised to charge with any C type charger.  When plugged into carjust now’ the little charge ion showed that it was charging’ but the power went down from 70% to 68%while plugged in.  I understand the original chargers are a bit pricy to replace’ plus’ you cannot use it anywhere without a wall socket, such as a car.  If you can help, that would be great.  Thank you