The phrase "are at disposal" implies that something is available or ready for use. If looking for antonyms, words like unavailable, inaccessible, or restricted come to mind. Other options might include words like unavailable, unattainable, unfriendly, and unresponsive. These are all words that convey some sense of limitation or unavailability. Conversely, synonyms for "are at disposal" include accessible, available, open, and ready. It is always best to carefully consider the tone, context, and audience when choosing words or phrases to convey a specific meaning or message.