First lesson learned. The first thing to learn about second hand bikes is skepticism., which you have just found out. Second thing is that really good deals are snapped up quickly by knowledgable buyers, so it is easy to either wait too long or buy without weighing the condition of the bike properly. Patience is important as is research. You can ask for online advice that most people in a forum like this are happy to provide, but getting an answer can take more time than it would take to get to get advice before a really good bike has been sold. Don't know where you live, but where I live it is slow season for cycling which can affect the number of second hand bikes going up for sale. The second hand market isn't anything like buying new where you simply research bikes according to what you want to do with them and how much you want to pay. Second hand deals mean that you have to wait for something to come up that meets your needs knowing full well that you might take many months to find something