I don't see why they shouldn't replace the battery. To be quite honest, everytime my girlfriend or I had trouble with an apple computer it was fixed without any cost. I do call tech support myself, I ask the telephone number and take care of it. The way I see it, direct communication leaves out more space for errors.

I don't know if this has anything to do with the fact I live in Belgium and warranty is 2years, I've had issues with my battery a couple of times but batteries don't fall under the 2year warranty so they aren't forced to replace it.