Welcome to MM. I agree that is not good service, I would ring his office again, run it past his secretary and then ask to speak to one of his nurses. If you don't get anywhere, just keep trying.
What type of HRT were you taking before and when did you last take progesterone? This would make a difference. I note you said you are taking progetesterone for 10 days as opposed to his usual 7 day dose, does this mean you don't normally have any problems with the progesterone part of HRT? If that is the case, you are very lucky!
I really wouldn't worry about the bleeding, it is common when starting a different type of HRT. Four pumps of Oestrogel is a high dose and if you haven't taken any progesterone for a while, it would cause breakthrough bleeding. However, once you start the progesterone at the beginning of August, the bleeding should settle down and your body will find a natural level and you will get into a routine with schedule bleeding and after a while, it usually becomes lighter.