Iphone 4 16GB Black Faluty No Signal Mint Condition. !

Hi There , I have my old iphone 4 16GB Black for sale very well look after it, all good with Cydia and Instalous on it but i sell as faulty no signal bar ...i don`t know what is this error ,i bot it brand new free sim 1year and 4 mounts ago For more info Please Call John on 07500104501 Thank You