NSData is not in a format where you can go through to parse it. Just convert it to a NSString like this:
-(void)parseData:(NSData *)responseData
{
NSString *stringFromData = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
NSArray *eachLineOfString = [stringFromData componentsSeparatedByString:@"\n"];
for (NSString *line in eachLineOfString) {
// DO SOMETHING WITH THIS LINE
}
}