HTC Wildfire S — lines on middle of the screen

Address:

Visakhapatnam, Andhra Pradesh

i got line on my screen with out any reason... actually my touch screen got problem due to fell on surface nd went to servicing centre and thay repalced new touch screen part and charged nearly 3000 rs..it hapns not more than 6 months.. this screen was fitted one in past by u r service centre...now i got problem with screen which is replaced by u r service centre ...now i want sollution ...what to do now...please c in picture ...a black line on screen top