I have a cheapo Sainsbury's T-Mobile PAYG mobile made by Samsung, its about 6 months old and has no designation nunmber/letters. Its black with screen above key board, no camera or other fancy accessories. I cant find my instruction book a nd have somehow turned my riner off. on screen at top left an ico of a pair of headphones appeared yesterday and I cant get rid of it or restore setting. Anybody out there who could help please