These two phrases never cease to confuse me. I always say:
- Je les ai envoyeur mon message
- Je les ai dit de ne pas me perturber
- Je les avais fait comprendre la phrase ...
So on so forth. I can not distinguish when it is appropriate to use "Je leur ai...".
For me, "Je les ai.." sounds a lot similar in meaning to "I ... them"
Is there some sort of mnemonical solution to understand their use-cases?