Temperance isn't just blending and mixing, it's about the right conditions, finding the correct balance/blend for the desired outcome (a bit like following a recipe).
Patience, definitely. It may be Temperance is telling you when the time is right, then this person will contact you, they may have too little time, other priorities or something else that is delaying contact.
You could ask your cards 'what would be the outcome if you contacted them?' That may help you decide if it should be up to you to make the call.