this means he or she is not available at the moment. He or she is in a meeting or conversation with a client, and does not have time to talk to you right now. He or she will get back to you in time. Hope this helps

or you could contact him or her later on, to tell the truth, it does not say, if they will contact you, or you should contact them. I do not know the situation, therefore I cannot tell. If they wanted to get back to you themselves, they would probably have said something like "melde mich später"