I know from personal experience that the people at Hombu Dojo are not "un-enthusiastic". They work very hard on behalf of Aikido, and have many things to tend to.
It makes sense that they can't realistically take care of every single person who wants to come to train at Hombu. The International Office takes care of Aikido organizations and dojo, not individual people.
The scope of what they do is hard to understand unless you've seen it. If you did, you'd probably think twice before adding to what you expect them to be doing by asking them to respond to your personal needs.
There are a few people on this list currently living in Tokyo. I suggest you ask them for referrals for places to stay. Good luck!
Yeah.. I would like to support Lisa's comments. Expecting the hombu dojo office to be a service facility to handle such things would probably not get you in good standing with the staff. They have to focus their energy on doing the tasks that they are hired to do.
Also: In the Japanese society (as well as in the Aikikai organisation) having a sense of timing and appropriate attitude is crucial. Much more so than most other countries I've been to. So it is well worth spending some time reflecting on that before going there.