@JenniferSaoirse Hi! It might help to have a few more details. It does seem odd that you need to repeat yourself often. Sometimes people will ask you to repeat if they aren't getting it for some reason or another. They also repeat questions when they get an answer they do not like. Do you believe there is some kind of intentional harassment involved here?
The short answer is you tell people what you need them to know as often as it takes to reach some kind of understanding. I'd recommend answering his question in a different way and maybe a different format the next time it's asked. For example, if you tell him in writing one time try telling him via text or over the phone the next time. Be sure to record any unwritten communication if you feel like you are being intentionally harassed.