What should I do if my phone is reverse charging?
I believe you mean to say that your battery is discharging when you connect it to the charger. It really means that your battery is discharging. Simple thing you have to understand is current flows from higher voltage point to lower voltage point.If the supply voltage is higher than the battery voltage, current flows into the battery and the battery charges. If the supply voltage is less than the battery voltage, then the currrent flows from battery to the charger and the battery discharges (reverse charges). The second case happens very rarely. Generally if you try to charge your phone through laptop or computer USB port this happens. Sometimes the USB port supply voltage is less than the battery voltage and your battery discharges. So, it is better to charge battery from wall inlets (230v mains) using your phone charger.