DELL INSPIRON-5570

DEAR ALL HOW ARE YOU? i'm fine,but so confused about my dell inspiron-5570. my brother bought me this laptop from Kuwait on August 24 2018 ,who is working there.when he come to our home country Ethiopia on august 25 2018 he come with new dell inspiron-5570,receipt,warranty card from retailer shop,manuals. all things were so good. but within a month my laptop stopped charging. i tried all necessary things i heard on this forum and from dell site but nothing,at last my battery became empty and my laptop couldn't start so i took it to the repair shop and they unplug ram,hdd,but can't turn on when they unplug battery cable it turns on and works fine but when plugin the battery nothing the led blinks and off so not charge. the technician told me that the charger is healthy mother board is also fine and the power from ac adapter reach up-to battery, so he said the battery is fault,but i couldn't believe him because it is new even i couldn't used software which cause the laptop hot.now i'm using the laptops without battery only on ac adapter. but there is warning that says ac adapter is unknown ,''the ac adapter wattage and type cannot be determined .the battery battery may not charge. the system will adjust the performance to match the power available'' i also changed the adapter but same, i really disappointedby dell what can i do????? pls help!!! sorry for my English and inconvenience I've made!!