How advanced are you? Putting spurs on just after 6 months of lessons doesn't sound quite right to me unless you had plenty of riding experience before switching to dressage. Not a critique from me, but there is a time and place for any extra-equipment. If you horse doesn't respond well to your legs I doubt spurs will help much.
I never lunge either my or lesson (the client's, very forward) horse before the lesson. I don't see a big need unless you have a cold-backed horse. Not saying anything wrong with lunging (I know some people like it), but it's not something I'd worry about in the instructor. However if you try to do something for just 10 secs and if you can't the instructor makes you to switch to something else, I don't quite understand. If you can't achieve something the instructor should explain you (or even show you) how to do it and why it should be done this way and you have to try it at least several times. Personally I wouldn't be very happy about it.
Frankly, sounds like you are not very happy about your instructor (no offense)!