Around mid June, 2013 I would attend meetings and run errands and, sometimes my E320 would start and other times it would not. It was a problem because I needed a dependable car, so I took it to a Mercedes mechanic and they changed the battery ,and I took it home, but after about a day, the same problem occurred. I took the car back and they said it must be a bad battery, changed it and before the day was over the problem reoccurred. I took it to another They kept my car for two weeks trying to figure out what the problem was because the car neither started nor not started consistently, so they were confused about what the problem was. They then called me and said it is one of two things: the ignition switch , which would be about $1000 to $1100 to fix or another part that would be about $1700 0r $1800. They told me that they would fix the ignition switch first and if it wasn't that it would be the other problem and the ignition switch would not be taken out or refunded. The problem is that I do not have $2800 laying around in case one part doesn't work. I need to know precisely what the problem is. The other question is how sure are they???