My On/Off button on my iPhone 4S (64 GB) has stopped working. The button stays all the way down now and I have to press really hard with my 2 thumbs to turn the phone off. I have already ordered an iPhone 5s and it will be here Thursday, but I was planning on selling my old iPhone 4S. I don't have Apple Care. I also looked at Gazelle and they said that they would give me $70 for it because of its broken On/Off button. What should I do?