Test the same cable and charger with any other device that can use it, if the other device works then you need to look inside your phone connector and look for dust, dirt, lint or anything that could have lodged inside and is stopping the cable to lock in place correctly, if nothing is there and cable locks properly and does not charge at all, then your phone needs to be repaired, it could be the charging port that needs to be replaced or the battery is damaged-shorted