You may call the 800 number, but it is unclear whether more information is available. It has only been three weeks. If you have an attorney who filed the form I-589, then the attorney may be able to check with asylum office, where your hearing will take place.
In general, it can take more time to schedule an interview, so you should use the time to continue to locate and secure documentation to prove your asylum claim and prepare for the hearing. It can be very difficult to prove a well founded fear of persecution in many situations.
The above is general information and does not create an attorney-client relationship.