Bought a refurbished Note 5 but would not switch on or charge. Ebay seller suggested hard reset. I've tried this but it's not progressing - Galaxy start up screen appears followed by screen saying 'installimg system update' which in a flash changes to a warning screen - yellow triangle, white Android leaning over & msg saying 'no command'. It is cycling through these three screens without end. Any help would be appreciated, to save me the trouble of packing it back to the seller! Thanks.