Follow these rules to keep the Shell and ZNC username:

For the request to be successful:

  1. At least one nick must be registered in ILoveIRC
  2. A nickname registered in ILoveIRC must be sent in the request
  3. The request must have the same email with which the nick was associated, to avoid using the registered nick of another user

Keep the usernames:

  1. The registered nick in ILoveIRC mustn't expire
  2. The registered nick must be connected to ILoveIRC through Shell or ZNC and it mustn't be inactive for more than 21 days